Electronic lamp - an electric vacuum device (electrovacuum devices - devices for generating, amplifying and converting magnetic energy, in which the working space is freed from air and protected from the surrounding atmosphere by a rigid gas-tight shell), the operation of which is based on a change in the flow of electrons (selected from the cathode and moving into vacuum) by an electric field generated by electrodes. Depending on the value of the output power, electron tubes are divided into receiving and amplifying lamps(output power - not more than 10 W) and generating lamps(over 10 W).
The use of an electron tube as the main element of a computer created many problems. Due to the fact that the height of the glass lamp is 7 cm, the machines were huge. Every 7-8 min. one of the lamps broke down, and since there were 15-20 thousand of them in the computer, it took a very long time to find and replace the damaged lamp. In addition, they generated a huge amount of heat, and special cooling systems were required to operate the "modern" computer of that time.
To understand the intricate schemes of a huge computer, whole teams of engineers were needed. There were no input devices in these computers, so data was stored in memory by connecting the right plug to the right socket.
Examples of machines of the 1st generation are Mark 1, ENIAC, EDSAC (Electronic Delay Storage Automatic Calculator), the first machine with a stored program. UNIVAC (Universal Automatic Computer). The first copy of Univac was handed over to the US Census Bureau. Later, many different Univac models were created, which were used in various fields of activity. Thus, Univac became the first mass-produced computer. It was also the first computer to use magnetic tape instead of punched cards.
When it became known in the USSR about the creation of the ENIAC machine in the USA, the development of the first, domestic, operating computer was started in the Academy of Sciences of Ukraine and the Academy of Sciences of the USSR. Information about developments in the West was fragmentary, and, naturally, the documentation on the first computers was not available to our specialists. Sergey Alexandrovich Lebedev was appointed the head of development. The development was carried out near Kyiv, in a secret laboratory in the town of Feofaniya. The small electronic computing machine (MESM) - that was the name of the brainchild of Lebedev and his laboratory staff - occupied an entire wing of a two-story building and consisted of 6,000 electron tubes. Its design, installation and debugging were completed in record time - in 2 years, by only 12 scientists and 15 technicians. Despite the fact that MESM was essentially just a model of an operating machine, it immediately found its users: a queue of Kyiv and Moscow mathematicians lined up for the first computer, whose tasks required the use of a high-speed calculator. In his first machine, Lebedev implemented the fundamental principles of building computers, such as:
- Ш availability of arithmetic devices, memory, input / output and control devices;
- ø encoding and storing the program in memory, like numbers;
- Ш is a binary number system for encoding numbers and commands;
- Ш automatic execution of calculations based on a stored program;
- Ø the presence of both arithmetic and logical operations;
- Ш hierarchical principle of building memory;
- Ш use of numerical methods for the implementation of calculations.
After the Small Electronic Machine, the first Large Electronic Machine was created - BESM-1, over which S.I. Lebedev was already working in Moscow, at the ITM and VT of the Academy of Sciences of the USSR. Simultaneously with ITM and VT and competing with them, the newly formed SKB-245 with its Strela computer was engaged in the development of computers.
BESM and "Strela" constituted the fleet of the Computing Center of the Academy of Sciences of the USSR, created in 1955, which immediately fell under a very heavy load. The need for ultra-fast (at that time) calculations was experienced by mathematicians, thermonuclear scientists, the first developers of rocket technology, and many others. When in 1954 the RAM of BESM was equipped with an improved element base, the speed of the machine (up to 8 thousand operations per second) turned out to be at the level of the best American computers and the highest in Europe. Lebedev's report on BESM in 1956 at a conference in the West German city of Darmstadt made a splash, since the little-known Soviet machine turned out to be the best European computer. In 1958, BESM, now BESM-2, in which the memory on potentialoscopes was replaced by a memory on ferrite cores and the set of commands was expanded, was prepared for mass production at one of the factories in Kazan. Thus began the history of industrial production of computers in the Soviet Union!
The element base of the first computers - electronic tubes - determined their large dimensions, significant power consumption, low reliability and, as a result, small production volumes and a narrow circle of users, mainly from the world of science. In such machines, there were practically no means of combining the operations of the program being executed and parallelizing the operation of various devices; commands were executed one after another, the ALU was idle in the process of exchanging data with external devices, the set of which was very limited. The BESM-2 operative memory, for example, was 2048 39-bit words; magnetic drums and magnetic tape drives were used as external memory. The process of communication between a person and a machine of the first generation was very time-consuming and ineffective. As a rule, the developer himself, who wrote the program in machine codes, entered it into the computer memory using punched cards and then manually controlled its execution. The electronic monster was given to the undivided use of the programmer for a certain time, and the efficiency of solving the computational problem largely depended on the level of his skill, the ability to quickly find and correct errors and the ability to navigate the computer console. Orientation towards manual control determined the absence of any possibilities for buffering programs.
Ecology of knowledge. Science and technology: The key to a fuel-free source of electricity is to obtain electricity directly from a conventional lamp pentode triode in unusual modes of their operation
Valery Dudyshev unraveled the secret of Nikola Tesla about his source of electricity on his electric car.
An energy revolution is brewing in the field of alternative energy
Nikola Tesla actually demonstrated a fuel-free electric car in operation back in 1931 in Buffalo (USA). Electricity in the electric motor on the car came from a mysterious box with radio tubes. But until now, this mystery of the source of electricity for an electric car remained unsolved.
The answer lies in obtaining electricity directly from a conventional tube triode-pentode in unusual modes of their operation. It is only necessary to ensure explosive electron emission from its cathode. As a result, from a tube triode it is possible to get into an electrical load connected to it in parallel - as much electricity - as we want (well, of course, within reason: let's say with a source output power of 5-10 kW). Explosive electron emission is the discovery of Academician G. Mesyats used in this invention. - is achieved in the triode by supplying a series of short-duration but high-voltage high-voltage pulses to the control grid of the triode.
Explosive electron emission from the cathode surface leads to the formation of an avalanche of electrons accelerated by the control grid and falling on the anode of the triode
As a result, this avalanche of electrons from the anode enters the electrical load and through it again to the anode of the triode. This is how a free electric current arises and is maintained in the “triode - load” circuit. In other words, in this mode, a conventional tube triode with a strong email. the field on the control grid becomes a free source of electricity.
Calculations show that an ordinary vacuum tube triode in this mode of operation makes it possible to obtain powerful electron emission in a tube triode and, after some refinement of the triode, to obtain free electricity from a conventional tube triode, and when the cathode and anode are cooled - from one radio tube to 10 kW - that's such miracles!
A very rational technical solution is the combination of a resonant Tesla transformer with a vacuum lamp. In this case, the explosive electron emission from the vacuum tube cathode is provided by the Tesla transformer itself.
Powerful field emission from the output winding of a Tesla transformer
A variant of the device using a Tesla transformer
Fig.1 Block diagram of the design of a source of free electrical energy. This device is made on the basis of combining a Tesla transformer and a spherical vacuum tube with a needle cathode.
Brief description of the design of the source of gratuitous electricity
Vacuum electron tube original design (circled by a dotted line) contains a spherical anode 1 in the form of an outer metal hollow evacuated sphere, inside which is placed a spherical cathode 2 with external needles. The outer sphere anode 1 is placed in the center of the cubic body 3 with internal electrical insulation. 4 Metal rods 5 are rigidly attached to the anode and cathode, which through holes 6 go outside the body 3 and are electrically connected through switches K2,3,4, respectively, to the output of the Tesla transformer 7 and the electrical load 8 connected to the ground electrode 9. Tesla transformer 7 is connected at the input by the key K1 to the primary low-power source of electricity 11 (for example, a Krona battery). Parallel to the output electrical load 8, a voltage converter 10 is connected through the key K4. It serves to convert the high-voltage output voltage from the anode 1 into standard electricity parameters of 220 volts 50 Hz)
The device works as follows: First, the key K1 (12) is used to connect the primary source of electricity 11 to the Tesla transformer 7. The output high-voltage voltage from its output is fed through the key K2 to the spherical needle electrode - cathode 2, which forms powerful electron emission from its needles. The flow of ejected electrons from the needles of the cathode 2 reaches the anode 1 and settles on its inner surface.
As a result, the outer surface of the spherical hollow anode 1 acquires an excess electric charge, i.e. electrically charged to high voltages. Then, after charging the spherical anode 1, it is connected electrically through the output rod electrode 5 with the key K3 to the electrical load 8 and the electric charge from the anode 1 begins to drain through the load 8 into the ground electrode 9 and through it to the Earth, i.e. in the electrical load 8, a useful electric current arises and useful electricity is generated. If it is necessary to obtain electricity in other payloads of standard parameters, a voltage converter is provided, including the K4 key.
Excess electricity in the load 8 compared to the cost of electricity from the primary source 12 for the operation of the Tesla transformer 7 is due to powerful avalanche field emission of electrons under the influence of huge electric forces of the electric field created by the secondary winding of the Tesla transformer on the needles of the spherical cathode 2
Tesla transformer is a source of powerful electronic emission. By means of a conventional vacuum tube (tube diode) this electron flow can be converted into usable electrical energy. More details in the article TESLA TRANSFORMER AS A SOURCE OF FREE ELECTRICITY.
Conclusion
The idea of free electricity from a triode is that it is quite possible to use an ordinary tube triode as a source of electricity, provided that there is a significant electron emission from the cathode!
To generate electricity in a conventional tube triode, you just need to apply a high voltage between the cathode and the accelerating grid, with + on the grid, and then, with the appearance of an electron emission stream, from the cathode and its acceleration + on the triode grid - on the anode of the triode - from the cathode will gush the flow of electrons is an electric current, which we close through the load on the cathode.
The larger the accelerating electric field between the cathode and the grid, the greater the electron emission from the cathode (up to explosive e-emission), which means the greater the useful electric current from the anode - e.g. load current.
So, if you create elementary normal conditions for the operation of a tube triode in such a free mode (after all, there are a huge number of electrons in the cathode material and will last for many years of operation), then we completely get gratuitous electricity in el. load at the ends of the triode - parallel to it. The effect is most easily obtained on a tube triode, because there is a vacuum in it. Consequently, electron emission and, moreover, explosive el. emission in it will arise most simply and especially effectively, in the presence of a large electric potential on the grid of an ordinary triode with vacuum inside its glass bulb. published
DP ____________2_2_0_3________gr_4_4_4________________
number of specialty and group
Reviewer __________________ _____К_у_д_р_я_ш_о_в_а____
signature i., o., surname
Head _______________ _____E_p_sh_t_e_y_n________
signature i., o., surname
Diploma student _________________ _____T_k_a_h_e_n_k_o_V_K__
signature i., o., surname
Saint Petersburg
Introduction. . . . . . . . . . . 3
1. General part
1.1. Description of the subject area. . . . . . 4
1.1.1. Electronic lamps. . . . . . . 4
1.1.2. Calculation formulas. . . . . . . eleven
1.2. Analysis of solution methods. . . . . . . thirteen
1.3. Survey of programming facilities. . . . . . fourteen
1.4. Description of the selected programming language. . . . sixteen
2. Special part
2.1. Formulation of the problem. . . . . . . . 23
2.1.1. Basis for development. . . . . . 23
2.1.2. Purpose of the program. . . . . . 23
2.1.3. Technical and mathematical description of the problem. . . . 23
2.1.4. Program requirements. . . . . . 24
2.1.4.1. performance requirements. . 24
2.1.4.2. reliability requirements. . . . . . 25
2.1.4.3. Requirements for technical equipment. . . . 25
2.2. Description of the scheme of the program. . . . . . . 26
2.2.1. Description of the scheme of the main program. . . . 26
2.2.2. Description of the scheme of the module for calculating thermal stresses in the MGP 26 anode
2.2.3. Description of the diagram of the plotting module. . . 27
2.3. Program text. . . . . . . . 28
2.4. Program description. . . . . . . . 33
2.4.1. General information. . . . . . . 33
2.4.2. Functional purpose. . . . . 33
2.4.3. Description of the logical structure. . . . . 33
2.5. Description of the program debugging process. . . . . 34
2.6. An example of the results of the program. . . . . 35
3. Economic justification of the projected program. . . . 36
4. Measures to ensure life safety. . . 40
4.1. The effect of electric current on the human body
4.2. Grounding devices
Conclusion. . . . . . . . . . . 42
Bibliography. . . . . . . . . . 43
Annex 1. Scheme of the program. . . . 44
Appendix 2. Screen forms. . . . 47
Appendix 3. Examples of errors. . . . 51
Over the past few years, the word "computer" has been used more and more often. If earlier only world-renowned firms owned computers, and programs were written in low-level languages, today almost every apartment has a computer, and programs are written in high-level languages. More than a million computers are sold annually in Russia. Modern computers have great capabilities: they make numerical calculations, prepare books for printing, create drawings, films, music, control factories and spaceships on them. The computer is a versatile and fairly simple tool for processing all kinds of information used by a person.
This thesis assignment will allow workers of factories and design bureaus to reduce the number and cost of models of designed devices. The developed program will provide the calculation of the temperature field in the body of the MGP anode during heating after turning on the device, as well as the thermal stresses arising in this case, which destroy the anode material. The results of this program will provide the necessary initial information for the analysis of thermal stresses in the anode body and the choice of operating modes that preserve the service life and ensure high reliability and durability of the devices.
A COMMON PART
Description of the subject area
Electronic lamps
Electronic tubes are used to generate, amplify, or convert electrical oscillations in various fields of science and technology.
The principle of operation of electronic lamps
The principle of operation of all radio tubes is based on the phenomenon thermionic emission- this is an increase in the speed of electrons to such that they fly out of a metal with a negative charge and can move directionally between the electrodes, creating an electric current. This also requires that they do not encounter obstacles, such as air molecules, which is why a high vacuum is created in the lamps. To obtain thermionic emission, the metal must be heated to approximately 2000 o K. It is most convenient to heat the metal filament electric current ( glow current), as in lighting lamps. Not every metal can withstand such a high temperature, most melt, because of this, in the first samples of electron tubes, purely tungsten filaments were used, which glowed to a white glow, hence the name "lamp". But such brightness is very expensive - you need a strong current (half an ampere for a receiving lamp). But soon a way was found to reduce the filament current. Studies have shown that if you cover tungsten with some other metals or their oxides (barium, strontium and calcium), then the release of electrons is facilitated (the so-called “work function” is reduced). To exit, less energy is required, and therefore a lower temperature. Modern oxidized filaments operate at a temperature of about 700-900 ° C, in connection with this, it is possible to reduce the filament current by about 10-20 times.
It should be noted that the control of all electron flows in the lamp is carried out by means of electric fields formed around electrodes with different charges.
Types of electronic lamps
Diode- a vacuum device that passes electric current in only one direction (Fig. 1a) and has two leads for inclusion in an electrical circuit (plus a glow lead, of course), a two-electrode lamp was invented in 1904 by physicist J. Fleming. Such an electronic lamp is a glass or metal container from which air is pumped out, and two metal electrodes: an incandescent cathode (-) and a cold anode (+). The cathode is of two types: direct heating and indirect heating. In the first case, the cathode is a tungsten filament (usually coated with oxide), through which the incandescent current passes, and in the second case, a cylinder covered with a metal layer with a low work function, inside which there is a filament electrically isolated from the cathode. The action of the cathode as a source of electrons is based on thermionic emission. Figure 1a shows the design of a vacuum diode with a directly heated cathode. The disadvantage of direct-heated cathodes is that they are not suitable for supplying them with alternating current, since when the current changes, the temperature of the filament has time to change, and the flow of emitted electrons pulsates with the frequency of the supply current, therefore indirectly heated cathodes are now used.
The current–voltage characteristic of the diode (Fig. 1f) is non-linear; this is explained by the accumulation of electrons near the cathode into a “cloud”. In the absence of an anode voltage, electrons are not attracted to it, and the anode current is zero. The anode current occurs when a positive voltage is applied to the anode, as the voltage increases, the anode current will increase (faster on the A-B curve). At a high voltage (at point B), the current strength reaches its maximum value - this is the saturation current. For a diode with an activated (oxide) cathode, there is no slowdown in the growth of the anode current, but at an anode current above a certain limit value, the cathode is destroyed. The properties of a diode are evaluated by the slope of the characteristic and the internal resistance of the lamp.
If the output of the grid is connected to the cathode, then there will be no electric field between the grid and the cathode, and the turns of the grid will have a very weak effect on the electrons flying to the anode - a quiescent current. If you connect a battery between the cathode and the grid so that the grid is negatively charged, then the latter will begin to repel electrons back to the cathode, and the anode current will decrease. With a significant negative potential of the grid, even the fastest electrons will not be able to overcome its repulsive effect, and the anode current will stop, i.e. the lamp will be locked. If the grid battery is connected so that the grid is positively charged relative to the cathode, then the resulting electric field will accelerate the movement of electrons. In this case, the meter in the anode circuit will show an increase in current.
The higher the grid potential, the greater the anode current becomes. In this case, some of the electrons are attracted to the grid, creating grid current, but with the correct design of the lamp, the number of these electrons is small. Only those electrons that are in close proximity to the turns of the grid will be attracted to it and create a current in the grid circuit - it will be insignificant.
The gain and power of triodes are different. With a high anode current, the anodes are subjected to strong electron bombardment, which leads to their significant heating and even destruction, so the anodes are made massive, blackened, special cooling fins are welded, or water cooling is used, which is described below. Water cooling is also used in the GI-11 (BM) pulse generator triode, recently developed by St. Petersburg scientists.
Screened lamps can work well with low grid voltages, but sometimes when tetrodes are operating, secondary electrons knocked out of the anode reach the screen grid, creating current and strong signal distortion - this phenomenon is called dynatron effect. Pentodes are the solution to this problem.
The way to eliminate the unpleasant consequences of the dynatron effect is obvious: it is necessary not to let secondary electrons into the screening grid. This can be done by introducing another grid into the lamp - the third in a row, which will protective, so we got pentodes - from the Greek word "penta" - five (Fig. 1d). The third grid is located between the anode and the screening grid and is connected to the cathode, therefore, it turns out to be negatively charged relative to the cathode. Therefore, secondary electrons will be repelled by this grid back to the anode, but at the same time, being quite rare, this protective grid does not interfere with the electrons of the main anode current. In modern (for 1972) high-frequency pentodes, the gain reaches several thousand, and the grid-anode capacitance is measured in thousandths of a picofarad. This makes the pentode an excellent lamp for amplifying high frequency oscillations. But pentodes are also used with great success to amplify low (sound) frequencies, in particular in final stages.
Structurally, low-frequency pentodes are somewhat different from high-frequency ones. To amplify low frequencies, it is not necessary to have too large gains, but it is necessary to have a large rectilinear section of the characteristic, since large voltages have to be amplified, therefore relatively rare screening grids are made. In this case, the gain does not turn out to be very large, but the entire characteristic is shifted to the left, so a larger section of it becomes usable. Low-frequency pentodes must deliver more power, therefore, they become massive and their anodes need to be cooled.
There are also Beam tetrodes- powerful low-frequency lamps without protective grids, in which the turns of the screening grids are located exactly behind the turns of the control grids. In this case, the electron flow is cut into separate beams (beams) flying directly to the anode, and it is carried a little further and the secondary electrons knocked out of it cannot reach the screening grid, but are attracted back by the anode without disturbing the normal operation of the lamp. The gain of such lamps is several times higher than that of conventional tetrodes, because electrons from the cathode fly in direct beams between the turns of the grids and do not scatter, but are directed to the anode by the field of shielding plates located on the possible leakage paths near the anode of the lamp, which are connected to the minus of the power source through the cathode. With ray lamps, it is possible to create a very advantageous shape of the characteristic, which makes it possible to obtain a large output power with a small signal voltage on the grid.
Radio tube designs
For low-power equipment, such as a radio receiver, lamps were tried to be made as small as possible (finger lamps). They are often called receiving-amplifying lamps. There are also subminiature lamps (pencil-thick) with soft leads. In powerful equipment of radio units and in radio transmitters, lamps of much larger sizes are used, which develop much more power in the anode circuit. Such lamps have massive anodes with forced air or water cooling. To do this, the anodes are made of copper or other heat-resistant metals, hollow ribs or tubes are welded to them, through which chilled water is passed. Powerful lamps with copper anodes and water cooling, invented in 1923 by M. A. Bonch-Bruevich, are used in powerful radio transmitters throughout the world (where semiconductor devices cannot be used).
There are several ways to cool the anode:
forced air;
forced water;
Natural (scattering).
To reduce the heating of the anode, it is often provided with ribs or wings.
During the existence of radio tubes, their design has undergone major changes. The first samples of receiving-amplifying lamps were quite large and consumed a very large filament current. With the improvement of designs and production technology, the size of the lamps decreased, the lamps became more durable, economical, and their quality improved. Receiving-amplifying lamps of our day bear little resemblance to the first radio tubes, although the basic principles of their operation have not changed.
Modern receiving-amplifying lamps are produced almost exclusively of the finger type (5-7 centimeters long). The internal fittings and leads of all electrodes are fixed directly on the flat glass bottom of the lamp and come out in the form of thin but strong pins arranged asymmetrically. Each of the pins is connected to the output of one of the lamp electrodes. The connection of electrodes (pinout) of lamps of the same type is always exactly the same.
To ensure the correct insertion of the lamp pins into the socket, two methods are used: an asymmetrical arrangement of the pins and the creation guide key on a plastic plinth (Fig. 1e), which enters the groove located on the panel.
In mass production, lamp anodes are cylindrical and made of copper or heat-resistant alloys. To simplify and reduce the cost of modeling and production of such electronic tubes, the developed program is intended.
Designs and designations of electronic tubes on diagrams
BUT) 
B) 
AT) 
G) 
D) 
E) 
a) - diode with direct heating (two designs and schematic designation);
b) - scheme of a triode with indirect heating (with a third electrode - a grid);
c) - design and schematic designation of a directly heated tetrode.
d) - design and schematic designation of a pentode with direct heating.
e) - the octal base of the radio tube with a guide (into the socket) ledge.
f) - anode current-voltage characteristic of the vacuum diode.
Calculation formulas
The temperature distribution over the anode wall thickness is determined by solving the differential equation:
the solution of which is subject to the boundary conditions:
On the inner (heated) surface:
(2)
On the outer (cooled) surface:
(3)
with initial condition: T(r,0) = T o = 300 o K. (4)
Equation (1) is integrated until the steady state is reached (heating is completed), i.e. the condition 
.
In equation (3): ε is the emissivity of the surface; σ o \u003d 5.67 * 10 -12 - Stefan-Boltzmann constant.
Based on the results of integrating equation (1), the thermal stress in the anode is calculated as:
(5)
T cf. (r,t) is the average temperature of the anode in the section with the coordinate r.
The integral in equation (5) is calculated by the Simpson method:
Where is the number of partitions n= 2m is even, and the step h = b-a/2m. M is the number of spatial intervals.
Formulas for calculating temperatures in finite difference representation:
Boundary conditions on the anode surfaces:
R int. : 
. (2’)
R outer: 
(3’)
Here: i, j are the numbers of spatial and temporal intervals, k is the outer wall;
Δr and Δ t are the steps of the space-time grid in coordinate and in time;
n is the number of spatial intervals within the thickness of the anode wall (R ext - R ext).
Designations adopted in the project:
R out, R int. are the outer and inner radii of the anode (cm);
t is the operating time after turning on the glow (sec);
r is the coordinate in the anode cross section (cm); R int. ≤ r ≤ R ex.
T(r,t) is the temperature in the section with coordinate ‘r’ at time ‘t’;
λ is the thermal conductivity of the anode material (W/cm*deg.);
α – thermal diffusivity of the anode material (copper=1.1);
E is the modulus of elasticity (kg/cm²);
α t is the coefficient of linear expansion (1/deg);
ε – surface emissivity;
σ o = 5.67 * 10 -12 (W / Cm 2 deg 4) - Stefan-Boltzmann constant;
q is the power supplied to the anode (W / cm²);
T 0 - ambient temperature (deg K).
Analysis of solution methods
The differential equation (1) - (3), (4) can be solved in two ways: an implicit (absolutely convergent) method and an explicit (relatively convergent) finite-difference approximation method. The difference between these methods lies in the fact that in the implicit method the step Δt is set to any value, while in the explicit method it is limited and taken very small.
This implies the difference in the conditions for the stability of schemes: .
In the explicit scheme ω<1/2, а в неявной схеме ω не ограничена. Это приводит к тому, что в явной схеме значение температуры в данный момент времени находится с помощью значения температуры в предыдущий момент времени, а в неявной схеме значение температуры в данный момент времени находится с помощью значения температуры в тот же момент времени.
The implicit scheme equation cannot be solved immediately, it is necessary to compose a system of equations, which greatly complicates the program scheme. The advantage of the implicit scheme is that by setting the desired step, you can drastically reduce the number of iterations, while in the explicit method the number of iterations will be tens of thousands. However, with modern computer speed, the difference of several thousand iterations during program operation will not be even a second, and a simple and convenient algorithm contributes to better and faster writing and debugging of the program. Therefore, when developing this program, an explicit method of finite-difference approximation was used.
Now we are accustomed to compact electronic devices and ultra-thin laptops. A little more than a hundred years ago, a device appeared that made this a reality and made a real revolution in the development of electronics. It's about the radio.
Tube intro
In circuitry, lamps used to be widely used, the first electronic devices were built using them. The golden time of radio tubes fell on the first half of the 20th century. For our grandfathers and great-grandfathers, giant computers were much more familiar, occupying an entire room and basking like infernal heat. You can't watch a TV show on a car like that.
Then there was a time when Soviet microcircuits became the largest in the world. But this is another story, which began after the advent of semiconductor devices. As you understand, this article is about the operation of a vacuum tube and its modern use.
Vacuum devices
Vacuum is the absence of matter. More precisely, its almost complete absence. In physics, high, medium and low vacuum are distinguished. It is clear that there can be no electric current in a vacuum, since the current is the directed movement of (particles) of charge carriers, which have nowhere to come from in a vacuum.
But is there really no way? Metals emit electrons when heated. This is the so-called thermionic emission. The operation of electronic vacuum devices is based on it.
Thermionic emission was discovered by Thomas Edison. More precisely, the scientist found out that when the filament is heated and there is a second electrode in the vacuum flask, the vacuum conducts current. Then Edison did not fully appreciate the significance of his discovery, but just in case he patented it. Conclusion: in any incomprehensible situation, patent!
Vacuum devices are hermetically sealed cylinders with electrodes inside. Cylinders are made of glass, metal or ceramics, having previously pumped air out of them.
In addition to vacuum tubes, there are the following vacuum devices:
- microwave devices, magnetrons, klystrons;
- kinescopes, cathode ray tubes;
- x-ray tubes.
The principle of operation of an electron lamp
A vacuum tube is an electronic vacuum device that works by controlling the intensity of the flow of electrons between electrodes.
The simplest type of lamp is a diode. Instead of reading the definitions, let's take a look at it.
In any lamp there is a cathode from which electrons fly out, and an anode to which they fly. If a “minus” is applied to the cathode, and “plus” to the anode, the electrons that have flown out of the hot cathode will begin to move towards the anode. Current will flow in the lamp.
By the way! If you need to calculate a diode amplifier, our readers now have a 10% discount on any kind of work
The diode has one-way conduction. This means that if a positive is applied to the cathode and a negative to the anode, there will be no current in the circuit.
In addition to these two electrodes, there may be others in the lamps.
All names of vacuum tubes are related to the number of electrodes. Diode - two, triode - three, tetrode - four, pentode - five, etc.
Let's take a triode. This is a diode in which an additional electrode is added - a control grid. Such a lamp with three electrodes can already work as a current amplifier.
If there is a small negative voltage across the grid, it will trap some of the electrons flying towards the anode and the current will decrease. With a large negative voltage, the grid “bans” the lamp, and the current in it stops. And if you apply a positive voltage to the grid, the anode current will increase.
A small change in the voltage on the grid, which is installed near the cathode, significantly affects the current between the cathode and the anode. This is the principle of amplification.
The use of electronic lamps
Almost everywhere the lamp was replaced by a semiconductor transistor. However, in some industries, lamps have taken their place and remain indispensable.
For example, in space. Lamp equipment withstands a wider range of temperatures and background radiation, therefore it is used in the production of spacecraft.
Air- or water-cooled lamps also find use in high-power radio transmitters.
Of course, it is difficult to imagine modern musical equipment without tube circuits.
Tube sound: fact or fiction?
Low-frequency amplifiers, or simply audio amplifiers, are the most famous modern application of radio tubes, which also causes a lot of controversy.
It comes down to "holivars" between adherents of tube and transistor sound. The tube sound is said to be more "soulful" and "softer" and pleasant to listen to. While the transistor sound is “soulless” and “cold”.
Nothing happens just like that, and it is unlikely that such disputes and opinions arose from scratch. At one time, scientists became interested in the question of whether tube sound is really more pleasant to hear. Quite a lot of research has been done on the difference between a lamp and a transistor.
According to one of them, tube amplifiers add even-numbered harmonics to the signal, which are subjectively perceived by people as "warm", "pleasant" and "cozy". True, how many people, so many opinions, so the debate is still ongoing.
Arguing is often a waste of time. But student service, on the contrary, will help save valuable man-hours. Contact our experts for quality assistance in any field of knowledge.
How lamp designations are deciphered, how lamp names are formed, what is the difference between multi-grid and multi-electrode lamps, how the electrodes of receiving lamps are displayed, etc.
How are lamp designations deciphered?
Receiving lamps produced by the Svetlana plant are usually indicated by two letters and a number. The first letter indicates the purpose of the lamp, the second - the type of cathode, and the number - the serial number of the development of the lamp.
The letters are deciphered as follows:
- U - amplifying,
- P - reception,
- T - translational,
- G - generator,
- Zh - low-power generator (old name),
- M - modulatory,
- B - powerful generator (old name)
- K - kenotron,
- B - rectifier,
- C is special.
The type of cathode is indicated by the following letters:
- T - thoriated,
- O - oxidized,
- K - carbonated,
- B - barium.
Thus SO-124 means: special oxide No. 124.
In generator lamps, the figure next to the letter G indicates the useful output power of the lamp, and for low-power lamps (with natural cooling) this power is indicated in watts, and for water-cooled lamps - in kilowatts.
What do the letters “C” and “RL” mean on the cylinders of our radio tubes?
The letter "C" in the circle is the brand of the Leningrad plant "Svetlana", "RL" - the Moscow plant "Radio lamp".
How are lamp names formed?
All modern radio tubes can be divided into two categories: single lamps, having one lamp in their cylinder, and combined lamps, which are a combination of two or more lamps, sometimes having one (common), and sometimes several independent cathodes.
For lamps of the first type, there are two ways of naming. The names compiled according to the first method indicate the number of grids, where the number of grids is indicated by the Greek word, and the grid is indicated by the English word (grid).
Thus, by this method, a five-grid lamp would be called a "pentagrid". According to the second method, the name indicates the number of electrodes, of which one is the cathode, the other is the anode, and all the rest are grids.
A lamp that has only two electrodes (anode and cathode) is called a diode, a three-electrode lamp is called a triode, a four-electrode lamp is called a tetrode, a five-electrode lamp is a pentode, a six-electrode lamp is a hexode, a seven-electrode lamp is a heptode, and an eight-electrode lamp is an octode.
Thus, a lamp with seven electrodes (anode, cathode and five grids) can be called a pentagrid in one way, and a heptode in another.
Combined lamps have names indicating the types of lamps enclosed in one cylinder, for example: diode-pentode, diode-triode, double diode-triode (the latter name indicates that two diode lamps and one triode are enclosed in one cylinder).
What is the difference between multi-grid and multi-electrode lamps?
Recently, in connection with the release of lamps having many electrodes, the following classification of lamps, which has not yet received general recognition, has been proposed.
It is proposed to call multigrid lamps such lamps that have one cathode, one anode and several grids. Multi-electrode lamps are those that have two or more anodes. A multi-electrode lamp will also be called one that has two or more cathodes.
The shielded lamp, pentode, pentagrid, octode are multi-grid, since each of them has one anode and one cathode and, respectively, two, three, five and six grids.
The same lamps as a double diode-triode, a triode-pentode, etc. are considered multi-electrode, since a double diode-triode has three anodes, a triode-pentode has two anodes, etc.
What is a Vari-Slope (“Varimyu”) Lamp?
Lamps with variable slope have the distinctive feature that their characteristic at small displacements near zero has a large slope and the gain increases to a maximum.
As the negative bias increases, the slope and gain of the tube decrease. This property of a lamp with a variable slope allows it to be used in the receiver's high-frequency amplification stage to automatically adjust the reception strength: with weak signals (small offset), the lamp amplifies as much as possible, with strong signals, the gain drops.
The figure on the left shows the characteristic of a 6SK7 variable slope lamp and the characteristic of a conventional 6SJ7 lamp on the right. A distinctive feature of a lamp with variable slope is a long “tail” at the bottom of the characteristic.
Rice. 1. Characteristics of the 6SK7 variable slope lamp and, on the right, the characteristic of the 6SJ7 conventional lamp.
What does DDT and DDP mean?
DDT is an abbreviation for a double triode diode, and DDP is an abbreviation for a double pentode diode.
The conclusions of the electrodes for various lamps are shown in the figure. (The marking of the pins is given as if looking at the base from below).
Rice. 2. How are the electrodes at the receiving lamps.
- 1 - direct filament triode;
- 2 - shielded direct filament lamp;
- 3 - two-anode kenotron;
- 4 - direct filament pentode;
- 5 - triode of indirect heating;
- 6 - shielded lamp with indirect incandescence;
- 7 - direct filament pentagrid;
- 8 - indirect filament pentagrid;
- 9 - double triode of direct heating;
- 10 - double diode-triode of direct heating;
- 11 - double diode-triode of indirect heating;
- 12 - pentode with indirect heating;
- 13 - double diode-pentode with indirect heating;
- 14 - powerful triode;
- 15 - powerful single-anode kenotron.
What is called lamp parameters?
Each vacuum tube has some distinguishing features that characterize its suitability for work in certain conditions, and the amplification that this tube can give.
These lamp-specific data are called lamp parameters. The main parameters include: the gain of the lamp, the steepness of the characteristic, internal resistance, quality factor, the value of the interelectrode capacitance.
What is gain factor?
The gain factor (usually denoted by the Greek letter |i) shows how many times stronger, compared to the action of the anode, the action of the control grid on the flow of electrons emitted by the filament.
The All-Union Standard 7768 defines the gain as “a parameter of a vacuum tube expressing the ratio of the change in the anode voltage to the corresponding reverse change in the grid voltage, necessary for the magnitude of the anode current to remain constant.”
What is slope?
The steepness of the characteristic is the ratio of the change in the anode current to the corresponding change in the voltage of the control grid at a constant voltage at the anode.
The slope of the characteristic is usually denoted by the letter S and is expressed in milliamps per volt (mA / V). The slope of the characteristic is one of the most important parameters of the lamp. It can be assumed that the greater the steepness, the better the lamp.
What is the internal resistance of a lamp?
The internal resistance of the lamp is the ratio of the change in the anode voltage to the corresponding change in the anode current at a constant voltage on the grid. The internal resistance is denoted by the letter Shi and is expressed in ohms.
What is the quality factor of a lamp?
The quality factor is the product of the gain and the steepness of the lamp, i.e., the product of i by S. The quality factor is denoted by the letter G. The quality factor characterizes the lamp as a whole.
The higher the quality factor of the lamp, the better the lamp. The quality factor is expressed in milliwatts divided by volts squared (mW/V2).
What is the internal equation of a lamp?
The internal equation of the lamp (it is always equal to 1) is the ratio of the steepness of the characteristic S, multiplied by the internal resistance Ri and divided by the gain q, i.e. S * Ri / c \u003d 1.
Hence: S=c/Ri, c=S*Ri, Ri=c/S.
What is interelectrode capacitance?
The interelectrode capacitance is the electrostatic capacitance that exists between the various electrodes of the lamp, for example, between the anode and cathode, anode and grid, etc.
The capacitance between the anode and the control grid (Cga) is of the greatest importance, since it limits the gain that can be obtained from the lamp. In shielded lamps intended for high frequency amplification, Cga is usually measured in hundredths or thousandths of a micromicrofarad.
What is the input capacitance of the lamp?
The lamp input capacitance (Cgf) is the capacitance between the control grid and the cathode. This capacitance is usually connected to the capacitance of the variable capacitor of the tuning circuit and reduces the overlap of the circuit.
What is the power dissipation at the anode?
During the operation of the lamp, a stream of electrons flies to its anode. Electron impacts on the anode cause the latter to heat up. If you dissipate (release) a lot of power on the anode, the anode may melt, which will lead to the death of the lamp.
The power dissipation at the anode is the limiting power for which the anode of a given lamp is designed. This power is numerically equal to the anode voltage multiplied by the strength of the anode current, and is expressed in watts.
If, for example, an anode current of 20 mA flows through a lamp at an anode voltage of 200 V, then 200 * 0.02 = 4 W are dissipated at the anode.
How to determine the power dissipation at the anode of the lamp?
The maximum power that can be dissipated at the anode is usually indicated in the lamp's passport. Knowing the power dissipation and given a certain anode voltage, it is possible to calculate what maximum current is permissible for a given lamp.
Thus, the power dissipation at the anode of the UO-104 lamp is 10 watts. Therefore, at an anode voltage of 250 V, the anode current of the lamp should not exceed 40 mA, since at this voltage exactly 10 W will be dissipated at the anode.
Why does the anode of the output lamp get hot?
The anode of the output lamp becomes hot because more power is released on it than that for which the lamp is designed. This usually happens when a high voltage is applied to the anode, and the bias set on the control grid is small; in this case, a large anode current flows through the lamp, and as a result, the dissipation power exceeds the allowable one.
To avoid this phenomenon, it is necessary to either reduce the anode voltage or increase the bias on the control grid. In the same way, it is not the anode that can be heated in the lamp, but the grid.
So, for example, screening grids are sometimes heated in shielded lamps and pentodes. This can happen both with too high anode voltage on these lamps and with a small bias on the control grids, and in cases where, due to some error, the anode voltage does not reach the anode of the lamp.
In these cases, a significant part of the lamp current rushes through the grid and heats it up.
Why have lamp anodes been made black lately?
Lamp anodes are blackened for better heat dissipation. A blackened anode can dissipate more power.
How to understand the readings of instruments when testing a purchased radio tube in a store?
The test setups used in radio stores to test purchased tubes are extremely primitive and do not really give a sense of the tube's suitability for operation.
All these installations are most often designed to test three-electrode lamps. Shielded lamps or high-frequency pentodes are tested in the same panels, and therefore the instruments of the test installation show the current of the screening grid, not the anode of the lamp, since a screening grid is connected to the anode pin on the base of such lamps.
Thus, if the lamp has a short circuit between the shielding grid and the anode, then this fault will not be detected on the test bench in the store and the lamp will be considered good. These devices can only be used to judge that the filament is intact and there is emission.
Can the integrity of its filaments be a sign of the lamp's suitability?
The integrity of the filament can be considered a relatively sure sign of the suitability of the lamp for operation only in relation to lamps with a pure tungsten cathode (such lamps include, for example, the R-5 lamp, which is currently out of production).
For preheated and modern direct-incandescent lamps, the integrity of the filament does not yet indicate that the lamp is suitable for operation, since the lamp may not have emission even with a whole filament.
In addition, the integrity of the filament and even the presence of emission does not yet mean that the lamp is perfectly suitable for operation, because there may be short circuits in the lamp between the anode and the grid, etc.
What is the difference between a complete lamp and an inferior one?
At lamp factories, all lamps are checked and inspected before leaving the factory. Factory standards provide for known tolerances for lamp parameters, and lamps that meet these tolerances, that is, lamps whose parameters do not go beyond these tolerances, are considered to be full-fledged lamps.
A lamp, in which at least one of the parameters goes beyond these tolerances, is considered defective. Defective lamps also include lamps that have an external defect, for example, crooked electrodes, a crooked bulb, cracks, scratches on the base, etc.
Lamps of this kind are labeled “inferior” or “2nd grade” and are put on sale at a reduced price. Usually defective lamps in terms of performance are not much different from full-fledged ones.
When buying defective lamps, it is advisable to choose one that has an obvious external defect, since such a defective lamp almost always has completely normal parameters.
What is a lamp cathode?
The cathode of the lamp is the electrode that, when heated, emits electrons, the flow of which forms the anode current of the lamp.
In direct filament lamps, electrons are emitted directly from the filament. Therefore, in direct-filament lamps, the filament is also the cathode. These lamps include UO-104 lamps, all barium lamps, kenotrons.
Rice. 3. What are direct filament lamps.
In a heated lamp, the filament is not its cathode, but is used only to heat the porcelain cylinder inside which this filament passes to the desired temperature.
A nickel case is put on this cylinder with a special active layer applied to it, which emits electrons when heated. This electron-emitting layer is the cathode of the lamp.
Due to the large thermal inertia of the porcelain cylinder, it does not have time to cool down during changes in the direction of the current, and therefore the background of the alternating current during the operation of the receiver will practically not be noticeable.
Heated lamps are otherwise called indirectly heated or indirectly heated lamps, as well as lamps with an equipotential cathode.
Rice. 4. What is a heated lamp.
Why are lamps made with indirect filament when it would be easier to make lamps with direct filament and thick filament?
If a direct filament lamp is heated with alternating current, then alternating current noise is usually heard. This noise is largely due to the fact that when the direction of the current changes and when the current drops to zero at these moments, the lamp filament cools somewhat and its emission decreases.
It would seem possible to avoid AC noise by making the filament very thick, since the thick filament will not have time to cool much.
However, it is very unprofitable to use lamps with such filaments in practice, since they will consume a very large current for heating. In addition, it should be noted that the background of the alternating current, when the filament is powered, occurs not only due to the periodic cooling of the filament.
The background to a certain extent also depends on the fact that the potential of the filament changes its sign 50 times per minute, and since the grid of the lamp in the circuit is connected to the filament, this change of direction is transmitted to the grid, causing the anode current to ripple, which is heard in the loudspeaker as a background.
Therefore, it is much more profitable to make lamps with indirect heating, since such lamps are free from the listed disadvantages.
What is an equipotential cathode?
An equipotential cathode is a heated cathode. The name “equipotential” is used because the potential is the same along the entire length of the cathode.
In direct-heated cathodes, the potential is not the same: in 4-volt lamps it varies from 0 to 4 V, in 2-volt lamps from 0 to 2 V.
What is an activated cathode lamp?
Vacuum tubes used to have a pure tungsten cathode. Significant emission from these cathodes begins only at very high temperatures (about 2400°).
To create this temperature, a strong current is needed and thus lamps with a tungsten cathode are very uneconomical. It was noticed that when the cathodes are coated with oxides of the so-called alkaline earth metals, the emission from the cathodes begins at a much lower temperature (800-1,200 °) and therefore a much weaker current is needed for the corresponding incandescence of the lamp, i.e., such a lamp becomes more economical in the consumption of batteries or accumulators.
Such cathodes coated with alkaline earth metal oxides are called activated, and the process of such coating is called cathode activation. The most common activator at present is barium.
What is the difference between thoriated, carbonated, oxide and barium lamps?
The difference between these types of lamps lies in the method of processing (activating) the cathodes of the lamps. To increase the emissivity, the cathode is covered with a layer of thorium, oxide, barium.
Lamps with a cathode coated with thorium are called thoriated. Barium-coated lamps are called barium lamps. Oxide lamps are also, in most cases, barium lamps, and the difference in their name is explained only by the way the cathode is activated.
For some (powerful) lamps, in order to firmly fix the thorium layer, the cathode is treated with carbon after activation. Such lamps are called carbonated.
Is it possible to judge by the color of the incandescence of the lamp about the correctness of the lamp mode?
Within certain limits, by the color of the glow, one can judge the correctness of the lamp's incandescence, but this requires a certain amount of experience, since lamps of different types have an unequal cathode glow.
Is it dangerous to heat the lamp base?
The heating of the lamp base during operation does not pose any danger to the lamp and is due to the transfer of heat from the cylinder and the internal parts of the lamp to the base.
Why in some lamps (for example, UO-104) is a mica disc placed inside the bulb against the base?
This mica disc serves to protect the base from the thermal radiation of the lamp electrodes. Without such a “thermal screen”, the lamp base would get too hot. Similar thermal screens are used in all high-power lamps.
Why is it that when you turn some lamps over, you can hear that something rolls inside their base?
Such rolling occurs due to the fact that insulators are put on the conductors that are inside the base and connect the electrodes to the pins when the lamps are pinned - glass tubes that protect the output conductors from shorting to each other.
These tubes in some lamps move along the wire when the lamps are turned over.
Why are the bulbs of modern lamps made stepped?
In lamps of the old type, the electrodes were fixed only on one side, in the place of the lamp where the posts on which the electrodes are fixed are connected to the glass leg.
With this mounting design, due to the elasticity of the holders, the electrodes are easily subjected to vibration. In the cylinders of modern lamps, the electrodes are attached at two points - at the bottom they are attached with holders to the glass leg, and at the top - to the mica plate, which is pressed into the "dome" of the lamp.
Thus, the whole design of the lamp becomes more reliable and rigid, which increases the durability of the lamps when they have to work, for example, in mobiles, etc. Lamps of this design are less prone to microphone effect.
Why are lamp bulbs covered with a silvery or brown coating?
For normal operation of the lamps, the degree of rarefaction of the air inside the cylinder (vacuum) must be very high. The pressure in the lamp is measured in millionths of a millimeter of mercury.
It is extremely difficult to obtain such a vacuum with the most advanced pumps. But even this rarefaction does not yet protect the lamp from further deterioration of the vacuum.
In the metal from which the anode and the grid are made, there may be an absorbed (“occluded”) gas, which, when the lamp is operating and the anode is heated, can then be released and worsen the vacuum.
To combat this phenomenon, when pumping out the lamp, it is introduced into a high-frequency field that heats up the lamp electrodes. Even before that, the so-called “getter” (absorber) is introduced into the cylinder in advance, i.e. substances such as magnesium or barium, which have the ability to absorb gases.
Dispersed under the action of a high-frequency field, these substances absorb gases. The sprayed getter is deposited on the bulb of the lamp and covers it with a coating that is visible from the outside.
If magnesium was used as a getter, then the balloon has a silvery tint, with a barium getter, the plaque turns golden brown.
Why do bulbs glow blue?
Most often, the lamp gives a blue gaseous glow, because gas has appeared in the lamp. In this case, if you turn on the lamp incandescence and apply voltage to its anode, the entire bulb of the lamp is filled with blue light.
Such a lamp is unsuitable for work. Sometimes, when the lamp is operating, the surface of the anode begins to glow. The reason for this phenomenon is the deposition on the anode and grid of the lamp of the active layer during the activation of the cathode.
In this case, only the inner surface of the anode often glows. This phenomenon does not prevent the lamp from working normally and is not a sign of its damage.
How does the presence of gas in the lamp affect the operation of the lamp?
If there is a gas lamp in the cylinder, ionization of this gas occurs during operation. The ionization process is as follows: electrons rushing from the cathode to the anode meet gas molecules on their way, hit them and knock electrons out of them.
The knocked-out electrons, in turn, rush to the anode and increase the anode current, while this increase in the anode current occurs unevenly, in jumps, and worsens the operation of the lamp.
Those gas molecules from which the electrons were knocked out and received as a result of this positive charges (the so-called ions) rush to the negatively charged cathode and hit it.
With significant amounts of gas in the lamp, ion bombardment of the cathode can lead to knocking off the active layer from it, and even to cathode burnout.
Positively charged ions are also deposited on the grid, which has a negative potential, and form the so-called grid ion current, the direction of which is opposite to the usual grid current of the lamp.
This ion current significantly impairs the operation of the cascade, reducing gain and sometimes introducing distortion.
What is thermionic current?
The electrons that are in the mass of a body are constantly in motion. However, the speed of this movement is so low that the electrons cannot overcome the resistance of the surface layer of the material and fly out of it.
If the body is heated, then the speed of the electrons will increase and in the end it can reach such a limit that the electrons will fly out of the body.
Such electrons, the appearance of which is due to the heating of the body, are called thermoelectrons, and the current generated by these electrons is called thermionic current.
What is an emission?
Emission is the emission of electrons by the cathode of the lamp.
When does a lamp lose emission?
Emission loss is observed only in activated cathode lamps. The loss of emission is a consequence of the disappearance of the active layer, which can occur for various reasons, for example, from overheating when a higher than normal filament voltage is applied, as well as in the presence of gas in the cylinder and the resulting ion bombardment of the cathode (see question 125).
What is receiver lamp mode?
The operating mode of the lamp is the complex of all constant voltages that are applied to the lamp, i.e., the filament voltage, the anode voltage, the voltage on the shielding grid, the bias on the control grid, etc.
If all of these voltages correspond to the voltages required for a given lamp, then the lamp is operating in the correct mode.
What does it mean to put the lamp in the desired mode of operation?
This means that all electrodes must be supplied with such voltages that correspond to those indicated in the lamp passport or in the instructions.
If the description of the receiver does not contain special instructions about the lamp mode, then you should be guided by the mode data that are given in the lamp passport.
What does the expression "lamp locked" mean?
By “locking” the lamp is meant the case when such a large negative potential is created on the control grid of the lamp that the anode current stops.
Such blocking can occur when the negative bias on the lamp grid is too large, as well as when there is an open in the lamp grid circuit. In this case, the electrons that have settled on the grid are unable to drain to the cathode and thus “lock” the lamp.
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