Lugansk association of radio amateurs - output contour system. Design features of high-power tube ra - continued How to set up a p circuit with an antenna

Output P-loop and its features

The P-loop must meet the following requirements:

Tune to any frequency of the specified range.

Filter, to the desired extent, the harmonics of the signal.

Transform, i.e. provide optimal load resistance.

Possess sufficient electrical strength and reliability.

Have good efficiency and simple, convenient design.

The limits of the real possibility of the P-loop, in terms of resistance transformation, are quite high and directly depend on the loaded quality factor of this P-loop. With an increase in which (hence the increase in C1 and C2), the transformation ratio increases. With an increase in the loaded quality factor of the P-loop, the harmonic components of the signal are suppressed better, but due to the increased currents, the efficiency of the loop drops. With a decrease in the loaded quality factor, the efficiency of the P-loop increases. Often, circuits with such a low loaded Q factor (“power squeeze”) cannot cope with harmonic suppression. It happens that with solid power, a station operating on a range of 160 meters is also audible on a range
80 meters or working on 40 meters is audible on 20 meters.
It should be remembered that "splatters" are not filtered out by the P-loop, since they are in its passband, only harmonics are filtered.

Influence of Roe on amplifier parameters

How does the resonant resistance (Roe) affect the parameters of the amplifier? The smaller Roe, the more resistant the amplifier to self-excitation, but the gain of the stage is less. Conversely, the larger Roe, the greater the gain, but the amplifier's self-excitation resistance decreases.
What we see in practice: let's take, for example, a cascade on a GU78B lamp, made according to the scheme with a common cathode. The resonant impedance of the stage is low, but the slope of the lamp is high. And for this we have, with this steepness of the lamp, a large gain of the cascade and good resistance to self-excitation, due to the low Roe.
The resistance of the amplifier to self-excitation also contributes to the low resistance in the control grid circuit.
An increase in Roe reduces the stability of the cascade in a quadratic dependence. The greater the resonant resistance, the greater the positive feedback through the capacitance of the lamp, which contributes to the emergence of self-excitation of the cascade. Further, the lower Roe, the greater the currents flow in the circuit, and hence the increased requirements for the manufacture of the output circuit system.

P-loop inversion

Many radio amateurs in the process of tuning the amplifier met with such a phenomenon. This happens, as a rule, on the ranges of 160, 80 meters. Contrary to common sense, the capacitance of the variable coupling capacitor with the antenna (C2) is unacceptably small, less than the capacitance of the tuning capacitor (C1).
if you adjust the P-circuit for maximum efficiency at the maximum possible inductance, then a second resonance occurs at this boundary. P-circuit with the same inductance has two solutions, that is, two settings. The second setting is the so-called "inverse" P-loop. It is named so because the capacitances C1 and C2 are reversed, i.e., the “antenna” capacitance is very small.
This phenomenon was described and calculated by a very old equipment developer from Moscow. In the forum under the tick REAL, Igor-2 (UA3FDS). By the way, Igor Goncharenko greatly contributed to the creation of his calculator for calculating the P-loop.

Ways to turn on the output P-loop

Circuit solutions used in professional communication

Now about some circuit solutions used in professional communications. The serial power supply of the output stage of the transmitter is widely used. Variable vacuum capacitors are used as C1 and C2. They can be both with a glass flask and radio-porcelain. Such variable capacitors have a number of advantages. They do not have a sliding current collector of the rotor, the minimum inductance of the leads, since they are ring. Very low initial capacitance, which is very important for high frequency ranges. Impressive quality factor (vacuum) and minimal dimensions. Let's not talk about two liter "banks" for a power of 50 kW. About reliability, i.e. about the number of guaranteed rotation cycles (back and forth). Two years ago, the old RA made on a GU43B lamp, which used a vacuum KPE of the KP 1-8 type, “left”
5-25 Pf. This amplifier has worked for 40 years and will continue to work.
In professional transmitters, variable-capacity vacuum capacitors (C1 and C2) are not separated by a separating capacitor, this imposes certain requirements on the operating voltage of the vacuum KPI, because it uses a series power supply circuit for the cascade and therefore the operating voltage of the KPI is chosen with a threefold margin.

Circuit solutions used in imported amplifiers

In the contour systems of imported amplifiers made on GU74B tubes, one or two GU84B, GU78B, the power is solid and the FCC requirements are very stringent. Therefore, as a rule, a PL circuit is used in these amplifiers. As C1, a two-section variable capacitor is used. One, small capacitance, for high-frequency ranges. In this section, the initial capacitance is small, and the maximum capacitance is not large, sufficient for tuning in the high-frequency ranges. Another section, with a larger capacity, is connected by a jack switch in parallel to the first section, for operation on low-frequency ranges.
The anode choke is switched by the same switch. On the high-frequency ranges, there is a small inductance, and on the rest, it is full. The circuit system consists of three to four coils. The loaded quality factor is relatively low, therefore, the efficiency is high. The use of a PL circuit results in minimal losses in the loop system and good harmonic filtering. On low-frequency ranges, contour coils are made on AMIDON rings.
Quite often I communicate via Skype with my childhood friend Christo, who works at ACOM. Here's what he says: the tubes installed in the amplifiers are pre-trained on the bench, then tested. If the amplifier uses two tubes (ACOM-2000), pairs of tubes are selected. Non-paired lamps are installed in the ACOM-1000 where a single lamp is used. The circuit tuning is done only once during the prototyping stage, since all amplifier components are identical. Chassis, component placement, anode voltage, inductor and coil data - nothing changes. In the production of amplifiers, it is enough to slightly compress or expand only the 10-meter range coil, the rest of the ranges are obtained automatically. The taps on the coils are soldered immediately during manufacture.

Features of calculations of output contour systems

At the moment, on the Internet, there are many "counting" calculators, thanks to which we are able to quickly and relatively accurately calculate the elements of the contour system. The main condition is to enter the correct data into the program. And this is where problems arise. For example: in the program, respected by me, and not only, Igor Goncharenko (DL2KQ), there is a formula for determining the input impedance of an amplifier according to a grounded grid circuit. It looks like this: Rin \u003d R1 / S, where S is the steepness of the lamp. This formula is given when the lamp is operating in the characteristic section with a variable slope, and we have an amplifier with a grounded grid at an anode current cutoff angle of about 90 degrees with grid currents. And so the formula 1 / 0.5S is more suitable here. Comparing the empirical calculation formulas both in our and in foreign literature, it can be seen that it will most correctly look like this: the input impedance of an amplifier operating with grid currents and with a cutoff angle of approximately 90 degrees R=1800/S, R- in ohms.

Example: Let's take the GK71 lamp, its steepness is about 5, then 1800/5=360 Ohm. Or GI7B, with a slope of 23, then 1800/23 = 78 ohms.
It would seem, what is the problem? After all, the input resistance can be measured, and the formula is: R \u003d U 2 / 2P. There is a formula, but there is no amplifier yet, it is only being designed! It should be added to the above material that the value of the input impedance is frequency dependent and varies with the level of the input signal. Therefore, we have a purely estimated calculation, because behind the input circuits we have another element, a filament or cathode inductor, and its reactance also depends on the frequency and makes its own adjustments. In a word, the SWR meter connected to the input will display our efforts to match the transceiver with the amplifier.

Practice is the criterion of truth!

Now more about the “counting”, only according to the calculations of the videoconferencing system (or, more simply, the output P-circuit). Here, too, there are nuances, the calculation formula given in the “counting room” is also relatively incorrect. It does not take into account either the class of operation of the amplifier (AB 1, B, C), or the type of lamp used (triode, tetrode, pentode) - they have a different KIAN (anode voltage utilization factor). You can calculate Roe (resonant impedance) in the classical way.
Calculation for GU81M: Ua=3000V, Ia=0.5A, Uc2=800V, then the amplitude value of the voltage on the circuit is (Uacont = Ua-Uc2) 3000-800=2200 volts. The anode current in the pulse (Iimp = Ia *π) will be 0.5 * 3.14 = 1.57A, the first harmonic current (I1 = Iimp * Ia) will be 1.57 * 0.5 = 0.785A. Then the resonant resistance (Roe \u003d Ucont / I1) will be 2200 / 0.785 \u003d 2802 Ohm. From here, the power given off by the lamp (Pl \u003d I1 * Ucont) will be 0.785 * 2200 \u003d 1727 W - this is the peak power. The oscillatory power, equal to the product of half the first harmonic of the anode current and the voltage amplitude on the circuit (Pk \u003d I1 / 2 * Ucont) will be 0.785 / 2 * 2200 \u003d 863.5 W, or easier (Pk \u003d Pl / 2). You should also subtract the losses in the loop system, about 10%, and we get about 777 watts at the output.
In this example, we only needed the equivalent resistance (Roe), and it is equal to 2802 ohms. But you can also use empirical formulas: Roe \u003d Ua / Ia * k (we take k from the table).

Lamp type	Amplifier class
Lamp type
Tetrodes	0,574	0,512	0,498
Triodes and pentodes	0,646	0,576	0,56

Therefore, in order to get the correct data from the “counter”, you need to enter the correct initial data into it. When using a calculator, the question often arises: what value of the loaded quality factor should be entered? There are several points here. If the transmitter power is high, and we only have a P-loop, then in order to “crush” the harmonics, we have to increase the load quality factor of the loop. And these are overestimated loop currents and, consequently, large losses, although there are pluses. With a higher quality factor, the shape of the envelope is “more beautiful” and there are no depressions and flattening, the transformation ratio of the P-circuit is higher. With a higher loaded quality factor, the signal is more linear, but the losses in such a circuit are significant and, therefore, the efficiency is lower. We are faced with a problem of a slightly different nature, namely, the inability to create a "full-fledged" circuit in the high-frequency range. There are several reasons - this is a large output capacitance of the lamp and a large Roe. Indeed, with a large resonant resistance, the optimal calculated data do not fit into reality in any way. It is practically impossible to make such an “ideal” P-contour (Fig. 1).

Since the calculated value of the “hot” capacitance of the P-circuit is small, and we have: the output capacitance of the lamp (10-30 Pf), plus the initial capacitance of the capacitor (3-15Pf), plus the inductor capacitance (7-12Pf), plus the mounting capacitance ( 3-5Pf) and as a result "runs" so much that the normal circuit is not realized. It is necessary to increase the loaded quality factor, and due to the sharply increased, at the same time, loop currents, a lot of problems arise - increased losses in the loop, requirements for capacitors, switching elements, and the coil itself, which should be more powerful. To a large extent, these problems can be solved by the series power supply circuit of the cascade (Fig. 2).

Which has a higher harmonic filtering factor than a P-loop. In the PL circuit, the currents are not large, which means there are less losses.

Placement of the coils of the output loop system

As a rule, there are two or three of them in the amplifier. They should be located perpendicular to each other so that the mutual inductance of the coils is minimal.
The taps to the switching elements should be as short as possible. The taps themselves are made with wide, but flexible tires with the appropriate perimeter, as, by the way, the coils themselves. They need to be located 1-2 diameters from the walls and screens, especially from the end of the coil. A good example of a rational arrangement of coils are powerful industrial imported amplifiers. The walls of the contour system, which are polished and have low resistivity, under the contour system there is a sheet of polished copper. The body and walls are not heated by the coil, everything is reflected!

Cold tuning of the output P-loop

Often at the “technical round table” in Lugansk, the question is asked: how, without the appropriate devices, to “cold” set up the output P-circuit of the amplifier and select coil taps for amateur bands?
The method is quite old and is as follows. First you need to determine the resonant impedance (Roe) of your amplifier. The Roe value is taken from the calculations of your amplifier or use the formula described above.

Then you need to connect a non-inductive (or low-inductance) resistor, with a resistance equal to Roe and a power of 4-5 watts, between the lamp anode and the common wire (chassis). The connection wires of this resistor should be as short as possible. The output P-loop is tuned when the loop system is installed in the amplifier case.

Attention! All amplifier supply voltages must be switched off!

The output of the transceiver is connected with a short piece of cable to the output of the amplifier. The "bypass" relay is switched to the "transfer" mode. Set the transceiver frequency to the middle of the desired range, while the internal tuner of the transceiver must be turned off. Served from the transceiver carrier ("CW" mode) with a power of 5 watts.
By manipulating the C1 and C2 tuning knobs and selecting the coil inductance or tap for the desired amateur radio range, a minimum SWR is achieved between the transceiver output and the amplifier output. You can use the built-in SWR meter in the transceiver, or connect an external one between the transceiver and the amplifier.
It is better to start tuning from the low-frequency ranges, successively moving to higher frequencies.
After tuning the output loop system, do not forget to remove the tuning resistor between the anode and the common wire (chassis)!

Not all radio amateurs are able, and financially including, to have an amplifier on lamps like GU78B, GU84B, and even GU74B. Therefore, we have what we have - as a result, we have to build an amplifier from what is available.

I hope this article will help you in choosing the right circuit solutions for building an amplifier.

Sincerely, Vladimir (UR5MD).

L. Evteeva
"Radio" №2 1981

The output P-circuit of the transmitter requires careful tuning, regardless of whether its parameters were obtained by calculation or it was made according to the description in the magazine. At the same time, it must be remembered that the purpose of such an operation is not only to actually tune the P-loop to a given frequency, but also to match it with the output impedance of the transmitter end stage and the impedance of the antenna feed line.

Some inexperienced radio amateurs believe that it is enough to tune the circuit to a given frequency only by changing the capacitances of the input and output variable capacitors. But in this way it is not always possible to obtain optimal matching of the circuit with the lamp and the antenna.

The correct setting of the P-loop can be obtained only by selecting the optimal parameters of all three of its elements.

It is convenient to tune the P-loop in a "cold" state (without connecting power to the transmitter), using its ability to transform resistance in any direction. To do this, a load resistance R1, equal to the equivalent output resistance of the terminal stage Roe, and a high-frequency voltmeter P1 with a small input capacitance are connected in parallel with the loop input, and a signal generator G1 is connected to the output of the P-loop - for example, to the antenna socket X1. Resistor R2 with a resistance of 75 ohms simulates the characteristic impedance of the feeder line.

The value of the load resistance is determined by the formula

Roe = 0.53Upit/Io

where Upit is the supply voltage of the anode circuit of the final stage of the transmitter, V;

Io is the constant component of the anode current of the terminal stage, A.

The load resistance can be made up of resistors of the BC type. It is not recommended to use MLT resistors, since at frequencies above 10 MHz, high-resistance resistors of this type have a noticeable dependence of their resistance on frequency.

The process of "cold" tuning of the P-loop is as follows. Having set the given frequency on the generator scale and entering the capacitances of the capacitors C1 and C2 to about one third of their maximum values, according to the readings of the voltmeter, the P-circuit is tuned to resonance by changing the inductance, for example, by selecting the tap location on the coil. After that, by rotating the knobs of the capacitor C1, and then the capacitor C2, you need to achieve a further increase in the voltmeter reading and adjust the circuit again by changing the inductance. These operations must be repeated several times.

When approaching the optimal setting, changes in the capacitances of the capacitors will less and less affect the readings of the voltmeter. When a further change in the capacitances C1 and C2 will reduce the readings of the voltmeter, the adjustment of the capacitances should be stopped and the P-circuit should be adjusted as accurately as possible to resonance by changing the inductance. On this, the setting of the P-loop can be considered complete. In this case, the capacitance of the capacitor C2 should be used by about half, which will make it possible to correct the circuit tuning when connecting a real antenna. The fact is that often antennas made according to descriptions will not be tuned accurately. In this case, the conditions for the suspension of the antenna may differ markedly from those given in the description. In such cases, resonance will occur at a random frequency, a standing wave will appear in the antenna feeder, and a reactive component will be present at the end of the feeder connected to the P-loop. It is from these considerations that it is necessary to have a margin for adjusting the elements of the P-loop, mainly capacitance C2 and inductance L1. Therefore, when connecting a real antenna to the P-loop, an additional adjustment should be made with the capacitor C2 and the inductance L1.

According to the described method, the P-circuits of several transmitters operating on different antennas were tuned. When using antennas that are sufficiently well tuned to resonance and matched with the feeder, additional tuning was not required.

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1 392032, Tambov Aglodin GA P KONTUR Peculiarities of the P circuit In the century of the victorious march of modern semiconductor technologies and integrated circuits, tube high-frequency power amplifiers have not lost their relevance. Tube power amplifiers, like transistorized power amplifiers, have their own advantages and disadvantages. But the indisputable advantage of tube power amplifiers is the work on a mismatched load without failure of electrovacuum devices and without equipping the power amplifier with special mismatch protection circuits. An integral part of any tube power amplifier is the anode P circuit fig. In the work r Method for calculating the P circuit of the transmitter, Konstantin Aleksandrovich Shulgin gave a very detailed and mathematically accurate analysis of the P circuit. Fig.1 In order to save the reader from searching for the necessary journals (after all, more than 20 years have passed), below are the formulas for calculating the P contour borrowed from: fo = f Н f В (1) geometric mean frequency of the Hz range; Qn X r = loaded quality factor of the P circuit; own quality factor of the P circuit, is mainly determined by the quality factor of the inductive element and has a value within (in some sources it is referred to as Q XX); own losses in the circuit, mainly in the inductor, are not subject to exact calculations, since it is necessary to take into account the skin effect and radiation losses in the field. This formula has an error of ±20%; N \u003d (2) the transformation ratio of the P circuit; equivalent resistance of the anode circuit of the power amplifier; load resistance (feeder line resistance, antenna input impedance, etc.); Qn η = 1 (3) Efficiency of the P circuit;

2 X = N η η (Qn η) N 1 Qn (4); X X = Qn X η (5); Qn X X = (6); η 2 2 (+ X) 2 10 = X 10 = 6 12 pf (7); X μH (9); 10 = 12 pf (8); X P circuit, on the one hand, is a resonant circuit with a quality factor Qn, on the other hand, a resistance transformer that converts the low-resistance load resistance into a high-resistance equivalent resistance of the anode circuit. Let us consider the possibility of transforming, using the P circuit, various values of the load resistance into the equivalent resistance of the anode circuit, provided that =const. Suppose it is necessary to implement a P circuit for a power amplifier assembled on four GU-50 pentodes connected in parallel according to a common grid scheme. The equivalent resistance of the anode circuit of such an amplifier will be \u003d 1350 Ohm (for each pentode 5400 ± 200 Ohm), the output power will be approximately R OUT W, the power consumed from the power supply P POT W. According to the given conditions: range 80 meters, fo = ff = = , H B =1350Ω, Qn=12, =200 according to formulas (1) (9) we will calculate for five values: =10Ω, =20Ω, =50Ω , \u003d 125 Ohm, \u003d 250 Ohm. The calculation results are shown in Table 1. Table 1 range 80 meters, fo= Hz, =1350Ω, Qn=12, =200 SWR N pf mkn pf,78 5.7 20 2.5 67.5 357.97 5.8 50 1.0 27.0 333.04 6.5 10.8 302.98 7.94 972.4 273.80 9.56 642.2 Similar calculations must be made for other ranges. More clearly, the change in the values of the elements, and on the load resistance are shown in the form of graphs as a function of Fig.2.

3 400 C1 pf μg 8.8 7.2 5, pf Fig. 2 Note the characteristic features of the graphs: the value of capacitance C1 decreases monotonically, the value of inductance increases monotonically, but the value of capacitance C2 has a maximum at =16 20 Ohm. It is necessary to pay special attention to this and take it into account when choosing the tuning range of capacitance C2. Moreover, the load resistance of a purely active character is quite rare, as a rule, the load resistance (antennas) is complex in nature and an additional margin is needed to compensate for the reactive component over the tuning range of the elements of the P circuit. But it is more correct to use an ACS unit (antenna matching device) or an antenna tuner. It is desirable to use ACS with tube transmitters, for transistor transmitters ACS is mandatory. Based on the above, we come to the conclusion that in order to match when the load resistance changes, it is necessary to rebuild all three elements of the P circuit of Fig. 3. Fig.3 Practical implementation of the P circuit Since the mid-60s of the last century, the scheme of the P circuit of Fig. 4 has been walking around, which seems to have taken root and does not cause much suspicion. But let's pay attention to the method of switching an inductive element in a P circuit. 1 2 S Fig.4 T Fig.5 S Whoever tried to switch the transformer or autotransformer in the same way Fig.5. Even one short-circuited turn can lead to a complete failure of the entire transformer. And with the inductor in the P circuit, we do the same without a shadow of a doubt!?

4 Firstly, the magnetic field of the non-closed part of the inductor creates a short-circuit current I short circuit in the closed part of the coil fig.6. For reference: the amplitude of the current in the P circuit (and in any other resonant system) is not so small: I K 1 A1 = = I Qn = 0.8A, where: I K1 is the amplitude of the resonant current in the P circuit; I A1 amplitude of the first harmonic of the anode current (for four GU-50 I A1 0.65A) (Fig. 4). Q-meter Fig.7 Q-meter Q \u003d 200 Q short circuit 20 a) b) Secondly, if it is possible to use a Q-meter (Q meter), take readings from an open inductor and with partially closed turns fig. 7a, fig. 7b Q OKZ will be several times less than Q, now using formula (3) we determine the efficiency of the P circuit: Qn 12 η = 1 = 1 = 0.94, 200 Qn 12 η KZ = 1 = 1 = 0.4?! kz 20 At the output of the P circuit, we have 40% of the power, 60% was spent on heating, eddy currents, etc. Summarizing the first and second, as a result, we get not a P circuit, but some kind of RF crucible. I KZ What are the ways of constructive improvement of the P circuit: Option 1, the circuit according to Fig. 4 can be modernized as follows: the number of inductive elements should be equal to the number of ranges, and not two or three coils as usual. To reduce the magnetic interaction of adjacent coils, their axes must be perpendicular to each other, at least in space there are three degrees of freedom, coordinates X, Y, Z. Switching should be carried out at the junctions of individual coils. Option 2 to use tunable inductive elements, such as variometers. Variometers will allow you to fine-tune the P circuit (Table 1 and Fig. 3). Option 3 to use a type of switching that excluded the presence of closed or partially closed coils. One of the possible options for the switching circuit is shown in Fig. 8.

5 M M M Fig. 8 Literature

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LABORATORY WORK Amplitude modulator The purpose of the work: to investigate a method for obtaining an amplitude-modulated signal using a semiconductor diode. Amplitude control of high-frequency oscillations

Laboratory work 6 Study of the local oscillator board of a professional receiver The purpose of the work: 1. To get acquainted with the schematic diagram and design solution of the local oscillator board. 2. Remove the main features

Ministry of Education and Science of the Russian Federation Kazan National Research Technical University. A.N.Tupolev (KNITU-KAI) Department of Radioelectronic and Quantum Devices (RECU) Guidelines

Sinusoidal current "in the palm of your hand" Most of the electrical energy is generated in the form of EMF, which varies in time according to the law of a harmonic (sinusoidal) function. Harmonic EMF sources are

03001. Elements of electrical circuits of sinusoidal current Purpose of work: To get acquainted with the main elements of electrical circuits of sinusoidal current. Master the methods of electrical measurements in sinusoidal circuits

Ways to turn on the transistor in the amplifying stage circuit As mentioned in Section 6, the amplifying stage can be represented by a 4-pole to the input terminals of which the signal source is connected a

State educational institution of secondary vocational education "Novokuznetsk College of Food Industry" WORKING PROGRAM OF THE DISCIPLINE Electrical and electronic engineering

Electromagnetic oscillations Quasi-stationary currents Processes in an oscillatory circuit An oscillatory circuit is a circuit consisting of an inductor connected in series, a capacitance capacitor C and a resistor

LABORATORY WORKS ON THEORETICAL FOUNDATIONS OF ELECTRICAL ENGINEERING Table of contents: ORDER OF PERFORMANCE AND REGISTRATION OF LABORATORY WORKS... 2 MEASURING INSTRUMENTS FOR PERFORMANCE OF LABORATORY WORKS... 2 WORK 1. LAWS

Mordovian State University named after N.P. Ogarev Institute of Physics and Chemistry Department of Radio Engineering Bardin V.M. RADIO-TRANSMITTING DEVICES POWER AMPLIFIERS AND TERMINAL CASCADES OF RADIO TRANSMITTERS. Saransk,

11. The theorem on an equivalent source. A - active two-terminal network, - external circuit Between parts A and there is no magnetic connection. A I A U U XX A I KZ

Coils and transformers with steel cores Basic provisions and ratios. A circuit with steel is an electrical circuit, the magnetic flux of which is wholly or partly enclosed in one

58 A. A. Titov

Part 1. Linear DC circuits. Calculation of the DC electric circuit by the folding method (equivalent replacement method) 1. Theoretical questions 1.1.1 Define and explain the differences:

3.4. Electromagnetic oscillations Basic laws and formulas Natural electromagnetic oscillations occur in an electrical circuit, which is called an oscillatory circuit. Closed oscillatory circuit

FOREWORD CHAPTER 1. DC CIRCUITS 1.1. Electric circuit 1.2. Electric current 1.3. Resistance and conductivity 1.4. Electric voltage. Ohm's law 1.5. Relationship between EMF and source voltage.

Page 1 of 8 The automatic antenna tuner of the branded transceiver completely refuses to match the input of the good old PA on a common grid tube. But the old home-made apparatus was coordinated and

Topic 11 RADIO RECEPTIONS Radio receivers are designed to receive information transmitted by electromagnetic waves and convert it to a form in which it can be used

List of topics of the program of the subject "Electrical Engineering" 1. Electric circuits of direct current. 2. Electromagnetism. 3. Electric circuits of alternating current. 4. Transformers. 5. Electronic devices and devices.

(v.1) Test questions on "Electronics". Part 1 1. Kirchhoff's first law establishes a connection between: 1. Voltage drops on the elements in a closed circuit; 2. Currents in the circuit node; 3. Power dissipated

LABORATORY WORK 6 Research of the air transformer. Job assignment .. In preparation for work, study:, ... Construction of an equivalent circuit for an air transformer ..3.

LABORATORY WORK 14 Antennas The purpose of the work: to study the principle of operation of a receiving-transmitting antenna, building a radiation pattern. Antenna parameters. Antennas are used to convert the energy of high currents

Work 1.3. The study of the phenomenon of mutual induction The purpose of the work: the study of the phenomena of mutual induction of two coaxially arranged coils. Devices and equipment: power supply; electronic oscilloscope;

\main\r.l. constructions\power amplifiers\... Power amplifier based on UM from R-140 based on UM from R-140 Brief technical characteristics of the amplifier: Uanod.. +3200 V; Uc2.. +950 V; Uc1-300V(TX), -380V(RX);

MOSCOW AVIATION INSTITUTE (NATIONAL RESEARCH UNIVERSITY) "MAI" Department of Theoretical Radio Engineering

MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION State educational institution of higher professional education - "Orenburg State University" College of Electronics and Business

LABORATORY WORK 1 STUDY OF A BROAD-BAND TRANSFORMER Objectives of the work: 1. Study of the operation of a transformer in the frequency range under harmonic and impulse effects. 2. Study of the main

Production of a transmitter for 2.8 3.3 MHz with amplitude modulation on a protective grid. To drive three GU 50 lamps into the control grid, you need from 50 to 100V RF voltage, with a power of not more than 1 W. And for

Topic 9. Characteristics, starting and reversing of asynchronous motors. Single-phase asynchronous motors. Topic questions .. Asynchronous motor with a phase rotor .. Performance characteristics of an asynchronous motor. 3.

1 option A1. In the harmonic oscillation equation q = qmcos(ωt + φ0), the value under the cosine sign is called 3) the charge amplitude A2. The figure shows a graph of the current strength in a metal