The power supply circuit with a stabilizer based on the P210 transistor is shown in Figure 1. At one time this was a very popular circuit. It could be found in various modifications, both in industrial equipment and in amateur radio equipment.
The entire circuit is assembled in a hinged manner directly on the radiator, using support stands and rigid transistor terminals. The radiator area at a load current of six amperes should be about 500 cm². Since the collectors of transistors VT1 and VT2 are connected, there is no need to isolate their cases from each other, but it is better to isolate the radiator itself from the case (if it is metal). Diodes D1 and D2 - any 10A. The area of radiators for diodes is ≈ 80 cm². You can roughly calculate the heat sink area for different semiconductor devices, so to speak, using the diagram given in the article. I usually use U-shaped radiators, bent from a strip of three-millimeter aluminum (see photo 1). 
Strip size 120x35mm. Transformer Tr1 is a rewound transformer from a TV. For example, TS-180 or similar. The diameter of the secondary winding wire is 1.25 ÷ 1.5 mm. The number of turns of the secondary winding will depend on the transformer you use. How to calculate a transformer can be found in the article, heading - “ Independent calculations" Each of windings III and IV must be designed for a voltage of 16V. By replacing the tuning resistor R4 with a variable one and adding an ammeter to the circuit, you can charge car batteries with this power supply.
Amateur radio VFO units on transistors Radio amateur D37AW has developed a highly stable transistor VFO at 5-5.5 MHz (see figure), which he uses in a transceiver of his own design. Careful thermal compensation of the circuit made it possible to reduce the generator frequency drift to 200 Hz in the temperature range from +10° C to +50° C. The VFO is made on two transistors, while the second transistor (T2) serves as a buffer stage. The load of the buffer stage is a low-pass filter with a cutoff frequency of 6 MHz. The circuit provides for a change in the oscillator frequency when changing the sideband in SSB mode, which allows you to avoid adjusting the transceiver when switching from VSB to LSB and vice versa. The frequency shift is carried out using a diode switch made on diode D1 and connecting capacitor C12 in parallel with capacitors C9 and C10 in VSB operating mode. To improve the stability of the VFO, the circuit is mounted on a chassis made of 3 mm thick aluminum sheet. Capacitor C2 has a positive TKE, C3-C5 and C7-C12 have zero. Coil L1 is wound on a ceramic frame, L2-L6 - on frames with ferrite cores. As D1, you can use diode D104. T1, T2 - transistors KT315A-B. "DL-QTC", 1969, N 1 1...
Double-gate field-effect transistor converter
Radio reception Converter on double-gate field transistors The converter, the diagram of which is shown in the figure, is designed to work together with radio receivers having a range of 80 m. It allows reliable reception of amateur radio stations on the ranges of 10 and 14 m. RF amplifier with tuned circuits at the input (L2CI) and output (L3C4) made on transistor T1. The second stage on transistor T2 works as a mixer and local oscillator. The local oscillator uses two quartz resonators. The main frequency of the first resonator is 17.5 MHz, the second - 24.5 MHz. A bandpass filter is enabled at the mixer output. The ratio of the number of turns of coil L1 to the number of turns of coil L2 is 3:7. Coil L4 contains 5.5 times more turns than L5. "QST" (USA), 1974. N 3 Transistors 40673 can be replaced with transistors of the KP306.1 series...
RADIO STATION WITH THREE TRANSISTORS
Radio transmitters, radio stations RADIO STATION WITH THREE TRANSISTORS The radio station is designed for two-way communication in the 27 MHz range with amplitude modulation. It is assembled using a transceiver circuit. The cascade on transistor VT1 serves as both a receiver and a transmitter. Amplifier on transistors VT1 and VT2 in receiving mode amplifies the signal isolated by the receiver, and in transmitting mode modulates the carrier. During installation, special attention should be paid to the location of capacitors C10 and C11. They are used to prevent self-excitation. If self-excitation does occur, then you need to connect several more capacitors of the same capacity. About setup. It's very simple. First, using a frequency meter, the frequency of the transmitter is set, and then the receiver of another radio station is adjusted for maximum noise suppression and maximum signal volume. Coil L1 tunes the transmitter, and coil L2 tunes the receiver. Tp1 - any small-sized output transformer. Ba1 - any suitable speaker with a winding resistance of 8 - 10 Ohms. Dr1 - DPM-0.6 or homemade: 75 - 80 turns of PEV 0.1 on a resistor MLT 0.5 W - 500 kOhm. The remaining parts are of any type. The coils are wound on frames with a diameter of 8 mm and contain 10 turns of PEV 0.5 wire. =Printed circuit board and circuit board - in Fig. 2 Printed circuit board and circuit board - in Fig. 2 TECHNICAL DATA Supply voltage - 9 - 12 volts Communication range in open areas - approximately 1 km. Current consumption: receiver -15 mA, transmitter - 30 mA. Telescopic antenna - 0.7 - 1m. Case dimensions - 140 x 75 x 30 mm. N. MARUSHKEVICH Minsk 1...
Wideband power amplifiers based on field-effect transistors
TRANSVERTER 14428 MHz
Radio transmitters, radio stations TRANSVERTER 144/28 MHz The transverter local oscillator has three stages. Output frequency - 116 MHz. The quartz oscillator is assembled on a KP312A transistor and operates at a frequency of 58 MHz. The resonator is vacuum. This is followed by a frequency doubler and local oscillator amplifier transistors type KT368A, KT355, 2T311. From the local oscillator the signal goes to the mixers of the receiving and transmitting paths. /img/ trsv1441.gif The mixer of the receiving path is assembled using a KP350 transistor. UHF at 144 MHz - at transistors type KT399, KT368, KT939. The transmitting path consists of four stages. Push-pull mixer transistors type KP350 and three-stage power amplifier - on transistors type KT939A (KT610A), KT904A, KT922 B(V). /img/ trsv1442.gif The transverter can be connected to any KB transceiver that has a 28 MHz range and smooth power control. MAIN TECHNICAL CHARACTERISTICS: Input power................no more than 100 mW Output power..............no less than 10 W Noise figure. ...............not worse than 1.5 dB (at Z=50 ohm) Load resistance.........75 Ohm Supply voltage...... .......24-28 V Current consumption in mode. before...no more than 3 A Connection procedure Connect the RX 28 MHz connector to the low-power output (no more than 0.5 W) of the KB transceiver. Connect a 144 MHz antenna with a resistance of 50 Ohms to the high-frequency “Ant” connector. Voltage 24-28 V is connected to pin 3 of the power connector, pin 2 is supplied with +24...28 V in transmission mode, pin 1 is supplied with 24... 28 V of the power supply (ground). When supply voltage is applied to the transverter, the KB noise of the transceiver increases in receive mode. In transmit mode, set the power adjustment knob KB of the transceiver to the minimum power position. Switch the KB transceiver and VHF transverter to transmit mode. Press the transmit key in the "telegraph" mode of the KB transceiver and smoothly increase the power of the KB transceiver until the arrow of the VHF transverter indicator reaches the red sector, then stop increasing the power. NIL RL (RL 2-91)1...
A simplified version of a power amplifier circuit based on complementary trans.
AUDIO technique A simplified version of the power amplifier circuit using complementary transistors It has the following main technical specifications(see also Table 4): Rated output power....... 70 W Harmonic distortion......... 0.05% Operating frequency band. . . . . . . . . . 20... 80,000 Hz Signal-to-noise ratio. . . . . . . . . . 87 dB Supply voltage......... ±40 V Quiescent current.............. 100 mA The amplifier operates in AB mode and is made using the circuitry of the previous amplifier. The amplifier also has complete symmetry for the input sinusoidal signal (the same input resistance for the positive and negative half-waves of the signal), which reduces nonlinear distortion. The schematic diagram of the amplifier is shown in Fig. 1. It contains a differential cascade on complementary transistors(VT1-VT4), voltage amplification stage (VT5, VT7) and output stage (VT8-VT13). The input stage supply voltage is stabilized (using zener diodes VD1, VD2). The output stage transistors are connected according to a common collector circuit. Temperature stabilization of the quiescent current of the output transistors is provided by diodes VD3-VD5 installed on a common heat sink with transistors VT12, VT13. Elements LI, R35, R36, C11, R20, C7 prevent self-excitation of the amplifier at high frequencies. Puc.1 Diodes VD3 - VD5 are located on the heatsink of the output transistors. Coil L1 contains 10 turns of PEV-2 0.8 wire wound on a resistor R35 (MLT-2). As with the previous amplifier, you first need to check the serviceability of all elements. After installation (checking its correctness), the amplifier, similar to the previous one, is connected to a power source. The setting is contained in setting resistor R29 the initial current of the output transistors within 50 ... 70 mA. The amplitude and phase-frequency characteristics of the adjusted amplifier are shown in Fig. 2. 1...
TRANSMITTER FOR "FOX HUNTING"
Radio transmitters, radio stations TRANSMITTER FOR "FOX HUNTING" V. KLEIMENOV, S. CHIKUTOV (UA3AGS) This transmitter can operate in two bands 3.5 (with A1 type modulation) and 144 MHz (with A2 type modulation). It contains separate radio frequency paths for each of the ranges and a common automatic manipulator, which consists of an electronic clock with a code generator 1...
Wideband aperiodic RF amplifier
For the radio amateur designer Wideband aperiodic HF amplifier The high-frequency amplifier offered to the attention of readers can find the widest possible application. This is an antenna amplifier for a radio receiver, and an amplification attachment for an oscilloscope with low sensitivity of the vertical deviation channel, and an aperiodic IF amplifier, and a measuring amplifier. The amplifier's input and output are designed to be connected to a line with a characteristic impedance of 75 Ohms. The operating frequency band of the amplifier is 35 kHz - 150 MHz with unevenness at the edges of the range of 3 dB. Maximum undistorted output voltage 1 V, gain (at 75 Ohm load) - 43 dB, noise figure at 100 MHz - 4.7 dB. The amplifier is powered from a 12.6 V source, current consumption is 40 mA. The schematic diagram of the amplifier is shown in the figure. It consists of two series-connected amplification cells, each of which has resistive amplification stages of transistors N1, T3 are loaded onto emitter followers at transistors T2, T4. To expand the dynamic range, the current through the last emitter follower is selected to be approximately 20 mA. The amplitude and frequency characteristics of the amplifier are formed by elements of the frequency-dependent feedback circuit R4C2, R10C5 and simple high-frequency correction chokes Dr1 and Dr2. Structurally, the amplifier is made on a printed circuit board made of foil fiberglass and placed in a silver-plated brass case. The connectors are high-frequency connectors SR-75-166 F. High-frequency chokes Dr1 and Dr2 are frameless. Their windings contain 10 turns of PEV-1 0.25 wire, the diameter of the windings is 5 mm. If 43 dB gain is excessive, only one gain cell can be used, depending on the intended purpose or transistors T1. T2 with supply voltage + 5 V, or transistors T3, T4 with a supply voltage of +12.6 V. In the first case, the noise figure is lower, but the maximum output voltage is also lower (about 400 mV); in the second case, the noise figure is slightly higher, but the maximum voltage across a 75 Ohm load is 1 V. The gain of both amplification cells is approximately the same (21-22 dB) over the entire range of the specified operating frequencies, and when using 1...
CASCODE AMPLIFIER
For the radio amateur designer CASCODE AMPLIFIER The cascode amplifier, the circuit of which is shown in the figure, is highly stable over a wide temperature range. Cascade on transistors V2, V3 form the most common cascode circuit - “common emitter - common base”, providing low input capacitance. The low output impedance of the entire amplifier is achieved by including an emitter follower on transistor V4 at its output. Conventional operating mode stabilization schemes are not applicable for cascode connections, since due to the high intrinsic gain it is impossible to use deep negative feedback without the risk of disrupting the stable operation of the amplifier. The required cascade offset is transistors V2 and V3 are set by a voltage divider formed by elements VI, R1 - R4. Because the divider current is the collector current of transistor V1. then any change in the temperature regime of the amplifier leads to a corresponding change in the base bias of transistors V2 and V3. It should be noted that for effective stabilization, transistor V1 must be of the same type as the others. It's even better if all four transistors are part of a transistor assembly made on a single silicon chip. The gain of the amplifier is equal to the ratio of the resistances of resistors R6 and R7 and is approximately 10 at a maximum output voltage amplitude of 3 V and a bandwidth of 6 MHz. "Radio, fernsehen, elekfronik" (GDR). 1978, N 9 Note. In a cascode amplifier, transistor assemblies 1MM6.0, KT365CA can be used. K1HT291. K1NT591. 1...
Device for monitoring the water level in the radiator
The device for monitoring the water level in the radiator is designed to signal a decrease in the water level, which will lead to overheating of the motor. The basis of the device is a multivibrator on transistors T2 and TZ. 1...
STABLE TRANSISTOR GENERATOR
Portable transistor radio
Radio transmitters, radio stations Portable transistor radio station at 144-146 MHz (RETRO) The schematic diagram of the radio station is shown in Fig. 1. It was made on four transistors. The transmitter is assembled according to a circuit with extraneous excitation. Oscillations at fixed frequencies in the range of 72-73 MHz, generated by an exciter assembled on transistor T3 (OS 614), are frequency modulated by applying alternating voltage from the carbon microphone capsule of the central bank to the base circuit of transistor T3. This voltage changes the dynamic capacitances of the transistor, which ultimately makes it possible to obtain very good frequency modulation with a frequency deviation of up to 0.5 MHz at a low supply voltage. Transistor T4 (AF 114) works as a doubler and power amplifier. In order to obtain the maximum output power at the permissible collector current of transistor T4, the bias voltage applied to its base can be adjusted using potentiometer R12. Since transistor T3 oscillates near its upper cutoff frequency, a limited voltage is applied to the emitter of transistor T4. Despite this, the output power of the transmitter in the range of 144-146 MHz reaches 1-2 mW. The receiver is assembled on transistors T1 (AF 114) and T2 (OS 604) and is a super-regenerator, the auxiliary frequency of which is selected in the range of 100-150 kHz. A tuned capacitor is used as a variable capacitor of the oscillating circuit (C1). All radio station coils are frameless and are wound on a mandrel with a diameter of 6 mm with a wire 1 mm thick. Coil L1 contains 6 turns. L2 and L3-3.5 turns, L.4-2.5 turns, L5-3 turns and L6-2 turns. The DR1 inductor is wound on a ferrite core with a diameter of 1.5-3 mm and contains 20-30 turns of PEL wire 0.3-0.5 mm. "Das Elektron", No. 14/15, 1962. The transistors of the radio station can be replaced with the following domestic ones: OS614 with P403 or P403A, AF 114 with P411 or P411A, OS 604 with P15 or P16. (RADIO No. 2 1963)1...
Direct conversion receiver
Radio reception Direct conversion receiver Recently, short-wave direct conversion receivers have become widespread. The figure shows circuit diagram one of these receivers, designed to operate in the 3.5 MHz range. Ohm consists of a high-frequency amplifier, a balanced mixer, a low-pass filter and a low-pass amplifier. The RF amplifier is made on field-effect transistor T1. Its load is the LIC3 circuit. From the symmetrical coil L3, the signal is fed to a balanced mixer, consisting of diodes D3, D4 and trimming resistor R3. Filters are included at the output of the balanced mixer. The field-effect transistor T3 is used as a master oscillator for the local oscillator (according to a three-point capacitive circuit). A buffer stage (transistor T2) is connected between the master oscillator and the mixer. The local oscillator supply voltage is stabilized. The low frequency amplifier is made of transistors T4 - TS. High-impedance headphones can be connected to its output. On transistors T7 and T8 (different structures) are the final stage of the amplifier. It is necessary when using low-impedance headphones or a direct-radiation dynamic head with a voice coil resistance of 8-30 Ohms. The receiver is mounted in a metal case measuring 105x90x50 mm. Coils L1, L2 and L3 are wound on frames with a diameter of 9.5 mm. and chokes Dr1 and Dr2 are on ferrite ring cores with a diameter of 10 mm. When making coils L1 and L2, 40 turns of PEV 0.31 wire are initially wound (turn to turn; coil L1). A layer of PEV 0.23 wire is wound on top of this layer (wound in two wires; coil L2). Coil L3 contains 40 turns of PEV 0.31 wire (wound turn to turn). The inductance of the inductor Dr1 is 1 mH, Dr2 is 60 mH. "Radio communication" (England). 1975, No. 2 Editor's note. The receiver can use KP303 transistors (T1, T3). KT315 (T2, T6, T7). KT342 (T4, T5), KT361 (T8), KD512A diodes (D1, D2). KD503A (D3, D4). D101 (D5, D6), zener diode KS156A (D7). RADIO N 7. 1975 1...
Substance identity determinant
The device is designed to test the identity of various substances: liquid, bulk, organic and mineral. The device allows you to compare identical substances and detect impurities in them. The main purpose of the device is express analysis, carried out according to the relative readings of the dial indicator. There are two holes in the housing rack into which test tubes are inserted. One test tube is with the sample substance, the other is with the substance being tested. The volume of substances in both test tubes is 30 ml. Each test tube is surrounded by plates of measuring capacitors C1 and C2. If both substances are identical, the capacitance of both capacitors will be equal and the indicator needle will remain at the control mark. If one of the substances contains impurities, the arrow will deviate from the mark. By the angle of deflection of the arrow one can judge the percentage of impurities. The basis of the device (Fig. 1) is a symmetrical multivibrator made on transistors VT2 and VT3. Capacitors C1 and C2 are measuring capacitors. If their capacitances are equal, the duty cycle of the pulses on the collectors of the multivibrator transistors is the same. But the duty cycle of the pulses can be completely defined; it is set by a variable resistor R3. Then the arrow of the indicator PA1, connected to the load resistors of the multivibrator through emitter followers on transistors VT1 and VT4 will be located on the “zero” division - the reference point of the device, or on any other division chosen arbitrarily (the accuracy of determining identity increases if the indicator arrow is on the right half of the scale). The average division of the scale is taken as “zero”. When there are substances of different composition between the plates, the capacitance of the capacitors will be different. There will be a kind of imbalance in the average voltages across the load resistors of the multivibrator and the indicator needle will deviate. Details All fixed resistors - MLT-0.25; capacitors - K50-6; SB1 - KM2-1; SA1 - TV1-1; RA1 - M4202. D. PLASCHINSKIY, Minsk. 1...
Power amplifier based on complementary transistors with full symmetry
AUDIO technology Complementary power amplifier transistors with full symmetry of the arms for both half-waves of the amplified signal and with a double differential cascade at the input. It has the following main technical characteristics: Rated output power....... 60 W Harmonic distortion......... 0.04% Operating frequency band......... 20 . ..150,000 Hz Signal-to-noise ratio......... 88 dB Supply voltage......... ±40 V Quiescent current......... ... 60 mA The amplifier is completely made on complementary transistors. It works in AB mode. The applied circuit solutions made it possible to reduce nonlinear distortions to a minimum. The main feature of the amplifier is the symmetry of the arms for both half-waves of the amplified signal. This made it possible to reduce the nonlinear distortion of the amplifier without introducing negative feedback. Another feature of the stands in the output stage circuit, which allows you to amplify the signal not only by current, but also by voltage. At the same time, the operating mode of the transients of the preliminary stage has been simplified, since the required signal amplitude is significantly less than for a conventional output stage. Puc.1 The circuit diagram of the amplifier is shown in Fig. 1. It contains a differential cascade on complementary transistors(VT1, VT4, VT2, VT5), voltage signal amplification stage)
