ULF circuit on germanium transistors MP39, P213 (2W). Transistors MP39, MP40, MP41, MP42 Transistor MP39 pinout

Transistors MP39, MP40, MP41, MP42.

transistors MP39, MP40, MP41, MP42- germanium, amplifying low-power low-frequency, p-n-p structures.
Glass-to-metal housing with flexible leads. Weight - about 2 g. Marking is alphanumeric, on the side surface of the case.

There are the following foreign analogues:
MP39 -2N1413
MP40 - 2N104
MP41 possible analogue - 2N44A
MP42 possible analogue - 2SB288

The most important parameters.

Current transfer ratio for transistors MP39 rarely exceeds 12 , for MP39B is in the range from 20 before 60 .
For transistors MP40, MP40A - from 20 before 40 .
For MP41 transistors - from 30 before 60 , MP41A - from 50 before 100 .
for MP42 transistors - from 20 before 35 , MP42A - from 30 before 50 , MP42B - from 45 before 100 .

Maximum voltage collector - emitter. For transistors MP39, MP40 - 15 in.
For MP40A transistors - 30 in.
The transistor MP41, MP41A, MP42, MP42A, MP42B - 15 in.

Current transfer ratio limit frequency (fh21e) transistor for circuits with a common emitter:
Before 0,5 MHz for transistors MP39, MP39A.
Before 1 MHz for transistors MP40, MP40A, MP41, MP42B.
Before 1,5 MHz for MP42A transistors.
Before 2 MHz for MP42 transistors.

Maximum collector current. - 20 mA constant, 150 mA - pulsating.

Collector reverse current at a collector-base voltage of 5V and an ambient temperature of -60 to +25 Celsius, no more than - 15 uA.

Reverse emitter current at an emitter-base voltage of 5V and an ambient temperature of up to +25 Celsius, no more than - 30 uA.

collector junction capacitance at a collector-base voltage of 5v at a frequency of 1 MHz - no more 60 pF.

Noise figure - for MP39B with a collector-base voltage of 1.5V and an emitter current of 0.5mA at a frequency of 1KHz - no more 12 db.

Collector power dissipation. For MP39, MP40, MP41 - 150 mW.
At MP42 - 200 mW.

Once upon a time, the transistors of this series were equipped with widely used beginner radio kits. MP39-MP42, with their rather large dimensions, long flexible leads and simple pinout (pinout), were ideal for this. In addition, a fairly large reverse current allowed them to work in a common emitter circuit, without additional bias. Those. - the simplest amplifier was going really, on one transistor, without resistors. This made it possible to significantly simplify the circuits at the initial stages of design.

Pinout transistor MP41

Designation of the MP41 transistor on the diagrams

On the circuit diagrams, the transistor is indicated both by a letter code and a conditional graphic. The letter code consists of the Latin letters VT and a number (serial number on the diagram). The conventional graphic designation of the MP41 transistor is usually placed in a circle, symbolizing its case. A short dash with a line from the middle symbolizes the base, two inclined lines drawn to its edges at an angle of 60 ° - the emitter and collector. The emitter has an arrow pointing towards the base.

Characteristics of the MP41 transistor

Structure p-n-p
15* (10k) V
20 (150*) mA
0.15W
30...60 (5 V; 1 mA)
Collector reverse current
>1* MHz
Structure p-n-p
Maximum allowable (pulse) collector-base voltage 15* (Zk) V
The maximum allowable direct (pulse) collector current 150*mA
Maximum allowable continuous collector power dissipation without heat sink (with heat sink) 0.2W
Static current transfer coefficient of a bipolar transistor in a common-emitter circuit 20...35* (1 V; 10 mA)
Collector reverse current - uA
Limiting frequency of the current transfer coefficient in a circuit with a common emitter >2* MHz

Pinout transistor MP42

Designation of the MP42 transistor on the diagrams

On the circuit diagrams, the transistor is indicated both by a letter code and a conditional graphic. The letter code consists of the Latin letters VT and a number (serial number on the diagram). The conventional graphic designation of the MP42 transistor is usually placed in a circle, symbolizing its case. A short dash with a line from the middle symbolizes the base, two inclined lines drawn to its edges at an angle of 60 ° - the emitter and collector. The emitter has an arrow pointing towards the base.

Characteristics of the MP42 transistor

- Structure p-n-p
- Maximum allowable (pulse) collector-base voltage 15* (Zk) V
- The maximum allowable direct (pulse) collector current 150*mA
- Maximum allowable continuous collector power dissipation without heat sink (with heat sink) 0.2W
- Static current transfer coefficient of a bipolar transistor in a common-emitter circuit 20...35* (1 V; 10 mA)
- Collector reverse current - uA
- Limiting frequency of the current transfer coefficient in a circuit with a common emitter >2* MHz

In the journals "YuT" No. 9 and No. 10 for 1970, we talked about simple detector receivers. Such receivers allow you to hear the signals of powerful and closely spaced radio stations in your headphones.

Today you will get acquainted with the simplest transistor amplifier, and also find out what needs to be done to make the receiver even better and how to "teach" it to receive more programs with increased volume.

So, SESSION 3.

WHAT A TRANSISTOR CAN DO

First of all, we need a transistor. This small electronic device, little more than a pea in size, performs the same role as an amplifier tube. The “heart” of a transistor is a miniature semiconductor plate (germanium or silicon) with two electrodes fused into it. One of the electrodes is called the emitter, the other is called the collector, and the plate is called the base (Fig. 1).

If a weak electrical signal is applied to the base of the transistor, then a powerful “copy” of it will appear in the collector circuit. It turns out that the semiconductor triode works as an amplifier. The ratio, which shows how many times the change in the collector current is greater than the change in the current in the base circuit that caused it, is called the current gain of the transistor and is denoted by the letter P (beta). You have already guessed that the greater the value of the coefficient |3, the greater the amplification of the triode.

d For a low-frequency amplifier, low-power transistors of the MP39-MP42 type or similar P13-P16 triodes with any letter index are suitable. It is important that their coefficient

current amplification factor was not less than 30-40.

In addition to the transistor T, the amplifier circuit (Fig. 2) includes a resistor R, a capacitor C and an electromagnetic telephone Tlf.

Resistor R is connected between the base of the transistor and the minus of the battery. It provides voltage supply to the base and creates the necessary operating mode of the triode. Its resistance is 200-300 kΩ and depends on the parameters of the transistor.

Capacitor C is called a separating capacitor. It lets sound signals through, but blocks the DC current path between the base and the positive battery terminal.

The fixed resistor R can be of any type. However, it is better to include small-sized devices such as ULM or MLT 0.125 in transistor circuits. Capacitor C with a capacity of 0.047 microfarads of the K Yu-7 or MBM type, and an electromagnetic telephone (earphone) TON-1 or TON-2 telephone with a high-resistance voice coil.

Assemble the amplifier circuit on a 50X30 mm cardboard or plywood circuit board (Fig. 3).

Transistors are very sensitive to high temperatures.

perature. It is necessary to solder quickly and confidently so as not to overheat the triode. The terminals of the device should not be bent closer than 10 mm from the body, and their length should be at least 15 mm.

Setting up the amplifier comes down to checking the operating mode of the transistor. Selecting the resistance value of the resistor R, set the collector current Ti equal to 0.8 - 1 mA. The measuring device must be connected between the earphone output and the battery minus. If you do not have a milliammeter or tester, then you can set the desired triode mode by maximum volume and good quality phone sound.

So, you have assembled a low frequency transistor amplifier. Connect a microphone to its input terminals

Low frequency. germanium alloy transistors-n- R MP39B, MP40A, MP41A are used to work in low-frequency amplification circuits and are produced in a metal case (Fig. 56, a - c) with glass insulators and flexible leads, weighing 2.5 g, with an operating temperature range from -60 to +70 ° WITH. Electrical parameters are given in table. 109.

Silicon transistors p-n-p MP 114, MP 115, MP116 are produced in a metal case with glass insulators and flexible leads (Fig. 57), weighing 1.7 g, with an operating temperature range of -55 to +100°C. Electrical parameters are given in table. 110.

Rice. 56. Pinout and overall dimensions of transistors MP39V, MP40A, MP41A (a) and their input (6) and output (c) characteristics in a circuit with a common base

Rice. 57. Pinout and overall dimensions of transistors MP114 - MP116

Table 109

Collector reverse current, μA, at U K b = - 5 V and temperature, °С:

20 ............... 15

70 ............... 300

Reverse emitter current, μA, at U Eb = - 5 V 30

The highest direct collector current, mA 20

Collector capacitance, pF, at U K6 =5 In and

f=500 kHz .............. 60

The highest impulse collector current,

mA, at I ESr<40 мА......... 150

Output conductivity, µS, at I e =1 mA,

U„ b \u003d 5 V and f \u003d 1 kHz .......... 3.3

Base resistance, Ohm, at I e \u003d 1 mA,

U kb \u003d 5 V and f \u003d 500 kHz ......... 220

Power dissipated by the collector, mW, at temperature, °С:

55 ............... 150

70................ 75

Negative voltage U e in, V .... 5

Table 110

Collector reverse current, mA, at U k = - 30 V and a temperature of 20 and 100 ° C, respectively ... 10 and 400

Reverse emitter current, μA, at U eb = - 10 V and a temperature of 20 and 100 ° C, respectively. . . - 10 and 200

Input resistance, Ohm, in the circuit with OB at LU= - 50 V, I e =1 mA, f=1 kHz....... 300

Power dissipated by the collector, mW, at 70°С .................. 150

Midrange. Transistors p-n-p KT203 (A, B, C) are used to amplify and generate oscillations in the range up to 5 MHz, to work in switching and stabilization circuits and are produced in a metal case with flexible leads (Fig. 58), weighing 0.5 g, with a range of operating temperatures from -60 to +125°С. The electrical parameters of the transistors are given in Table. 111.

Rice. 58. Pinout and overall dimensions of transistors KT203A - B

Table 111

Collector reverse current, μA, at the highest reverse voltage and temperature of 25 and 125 °C, respectively .............. 1 and 15

Reverse emitter current, μA, at U e 6 = - 30 V. 10

Collector junction capacitance, pF, at U K b = 5 V and f = 10 MHz .............. 10

Collector current, mA: constant ............... 10

impulsive............ . fifty.

Average value of the emitter current in the pulsed mode, mA .................. 10

Power dissipated by the collector, MW, at temperatures up to 70 °C......... V . . 150

* For transistors KT203A - K.T203V voltage u k q respectively equal to 50, 30 in 15 V,

high frequency. P-n-p conversion transistors GT321

(A - E) are produced in a metal case with flexible leads (Fig. 59, a), weighing 2 g, with an operating temperature range from - 55 to +60 ° C. The electrical parameters of the transistors are given in Table. 112.

There are the following foreign analogues:
MP39 -2N1413
MP40 - 2N104
MP41 possible analogue - 2N44A
MP42 possible analogue - 2SB288

The most important parameters.

Maximum voltage collector - emitter. For transistors MP39, MP40 - 15 in.
For MP40A transistors - 30 in.
The transistor MP41, MP41A, MP42, MP42A, MP42B - 15 in.

Maximum collector current. - 20 mA constant, 150 mA - pulsating.

Collector reverse current at a collector-base voltage of 5V and an ambient temperature of -60 to +25 Celsius, no more than - 15 uA.

Reverse emitter current at an emitter-base voltage of 5V and an ambient temperature of up to +25 Celsius, no more than - 30 uA.

collector junction capacitance at a collector-base voltage of 5v at a frequency of 1 MHz - no more 60 pF.

Noise figure - for MP39B with a collector-base voltage of 1.5V and an emitter current of 0.5mA at a frequency of 1KHz - no more 12 db.

Collector power dissipation. For MP39, MP40, MP41 - 150 mW.
At MP42 - 200 mW.

Pinout transistor MP41

Designation of the MP41 transistor on the diagrams

Characteristics of the MP41 transistor

Structure p-n-p
15* (10k) V
20 (150*) mA
0.15W
30...60 (5 V; 1 mA)
Collector reverse current
>1* MHz
Structure p-n-p
Maximum allowable (pulse) collector-base voltage 15* (Zk) V
The maximum allowable direct (pulse) collector current 150*mA
Maximum allowable continuous collector power dissipation without heat sink (with heat sink) 0.2W
Static current transfer coefficient of a bipolar transistor in a common-emitter circuit 20...35* (1 V; 10 mA)
Collector reverse current - uA
Limiting frequency of the current transfer coefficient in a circuit with a common emitter >2* MHz

Pinout transistor MP42

Designation of the MP42 transistor on the diagrams

On the circuit diagrams, the transistor is indicated both by a letter code and a conditional graphic. The letter code consists of the Latin letters VT and a number (serial number on the diagram). The conventional graphic designation of the MP42 transistor is usually placed in a circle, symbolizing its case. A short dash with a line from the middle symbolizes the base, two inclined lines drawn to its edges at an angle of 60 ° - the emitter and collector. The emitter has an arrow pointing towards the base.

Characteristics of the MP42 transistor

- Structure p-n-p
- Maximum allowable (pulse) collector-base voltage 15* (Zk) V
- The maximum allowable direct (pulse) collector current 150*mA
- Maximum allowable continuous collector power dissipation without heat sink (with heat sink) 0.2W
- Static current transfer coefficient of a bipolar transistor in a common-emitter circuit 20...35* (1 V; 10 mA)
- Collector reverse current - uA
- Limiting frequency of the current transfer coefficient in a circuit with a common emitter >2* MHz

A low-frequency power amplifier based on P213 germanium transistors, the schematic diagram of which is shown in Fig. 1 can be used to play a recording, as a low-frequency part of the receiver (from sockets Gn3, Gn4), as well as to amplify signals from sensors of adapted musical instruments (from sockets Gn1, Gn2).

The sensitivity of the amplifier from the sockets GnI, Gn2 - 20 mV, from the sockets Gn3, Gn4 - no worse than 250 mV;
Output power at a load of 6.5 ohms -2 watts;
coefficient of non-linear distortion - 3%;
Band of reproducible frequencies 60-12 000 Hz;
In silent mode, the amplifier consumes a current of about 8 mA, and in maximum power mode - 210 mA.
The amplifier can be powered by either batteries or 127 or 220 V AC.

circuit diagram

As seen from circuit diagram, the first amplification stage is assembled on a low-noise MP39B (T1) transistor according to a common emitter circuit. The amplified signal is fed to the potentiometer R1, from the engine of which, through the resistor R2 and the isolation capacitor C1, a low-frequency signal enters the base of the transistor. The load of the first stage of the amplifier is resistor R5.

The voltage divider R3, R4 and the resistor R6 are elements of temperature stabilization. The presence of the divider R3, R4 makes the voltage at the base of the transistor T1 little dependent on temperature. Resistor R6 in the emitter circuit creates negative DC feedback.

As the temperature rises, the current in the emitter circuit increases and the voltage drop across the resistor R6 increases. As a result, the voltage between the base and the emitter becomes less negative, which prevents the emitter current from increasing further. The second amplification stage is also assembled according to the scheme with a common emitter on the transistor MP39B (T2).

To reduce the dependence of the parameters of this cascade on temperature, it uses a combined negative feedback, determined by resistors R8, R9 and R10. The voltage amplified by the first stage is fed to the input of the second stage through the isolating capacitor C2. The load of the transistor T2 is the resistor R7.

The third amplification stage is assembled on a transistor T3. The load of the cascade is the resistor RI8. Communication between the second and third stages is carried out using capacitor C3.

The output stage of the amplifier operates in class B mode in a series-parallel circuit. The main advantage of amplifiers of this class over amplifiers operating in class A is a high efficiency.

When designing conventional low-frequency amplifiers, radio amateurs are faced with the task of manufacturing transition and output transformers. Small-sized transformers with a permalloy core are quite difficult to manufacture. In addition, transformers reduce the overall efficiency and in many cases are a source of non-linear distortion.

Recently, output stages without transformers have been developed - with quasi-complementary symmetry, that is, using transistors that have different types of transitions and complement each other to excite a push-pull amplifier.

The transformerless cascade is assembled on two power transistors T6, T7 with excitation from a pair of complementary symmetrical transistors T4 and T5, operating in the pre-terminal amplification stage. Depending on the polarity of the signal supplied from the collector of the transistor T3, then one (T4), then the other (T5) transistor is unlocked. At the same time, transistors T6, T7 associated with them open. If the amplified signal on the collector of transistor T3 has a negative polarity, transistors T4, T6 open, if the signal has a positive polarity, transistors T5 and T7 open.

The constant component of the collector current, passing through the thermostabilizing diode D1 and resistor R19, creates a bias at the bases of transistors T4, T5, which act as phase inverters. This offset eliminates the characteristic distortion caused by the non-linearity of the input characteristics at low base currents.

Resistors R22, R23 reduce the influence of the spread of the parameters of transistors T4, T3 on the operating mode of the output stage. Capacitor C9 is separating.

In order to reduce non-linear distortion, the amplification stages on transistors T3 - T7 are covered by negative AC feedback, the voltage of which is taken from the output of the final amplifier and is fed through the chain R17, C8, R16, R15, C6, R14 to the base of the transistor T3. In this case, the variable resistor R17 provides tone control in the low-frequency region, and the potentiometer R15 - in the higher frequency region.

If tone control is not required, then details R14 - R17. C6, C8 are excluded from the scheme. The feedback circuit in this case is formed by the resistor R0 (in Fig. 1 this circuit is shown by a dotted line).

For normal operation of the output stage, the voltage at point "a" (quiescent voltage) must be equal to half the voltage of the power source. This is achieved by appropriate selection of the resistor RI8. Quiescent voltage stabilization is provided by a DC negative feedback circuit.

As can be seen from the diagram, point "a" at the output of the amplifier is connected to the base circuit of the transistor TK using resistor R12. The presence of this connection automatically maintains the voltage at point "a" equal to half the voltage of the power source (in this case equal to ba).

For the normal operation of the amplifier, it is also necessary that the transistors T4, T5 and T6, T7 have as little reverse current as possible. The value of the gain (5 transistors T4-T7 should lie in the range of 40 - 60; moreover, the transistors can have different gains h. It is only necessary that the equality h4 * hb \u003d h5 * h7.

Details and installation

The amplifier is mounted on a getinax panel with a thickness of 1 - 1.5 mm. The dimensions of the board largely depend on the application of the amplifier. P213B transistors are equipped with radiators with a total cooling surface of at least 100 cm2 to ensure good heat dissipation.

The amplifier can be powered by a 12 V battery, assembled from Saturn-type cells, or from batteries for a flashlight. The amplifier is powered from the AC mains using a rectifier assembled in a bridge circuit on four diodes D1-D4 with a capacitive filter through a voltage stabilizer (Fig. 2).

As mentioned above, when the amplifier is operating, the current consumed by it varies over a fairly wide range. Sharp current fluctuations will inevitably cause a change in the magnitude of the supply voltage, which can lead to unwanted couplings in the amplifier and signal distortion. To prevent such phenomena, stabilization of the rectified voltage is provided.

The stabilizer includes transistors T7, T2 and a zener diode D5. This stabilizer, when the load current changes from 5 to 400 mA, provides a stable voltage of 12 V, and the ripple amplitude does not exceed 5 mV. Stabilization of the supply voltage occurs due to the voltage drop across the transistor T2.

This drop depends on the bias at the base of the transistor T2, which, in turn, depends on the value of the reference voltage across the resistor R2 and the voltage across the load (Rload).

Transistor T2 is mounted on a radiator. The rectifier is placed in a box measuring 60X90X130 mm, which is made of sheet steel 1 mm thick.

The power transformer is made on the Sh12 core, the thickness of the set is 25 mm. Winding I (for 127 V) contains 2650 turns of PEL 0.15 wire, winding II (for 220 V) - 2190 turns of PEL 0.12, winding III - 420 turns of PEL 0.55.

Adjustment

An amplifier assembled from proven parts and transistors usually starts working immediately. By connecting a power source (12 V), resistors R3, R8, R12, R18 set the recommended mode. Then, through the separating capacitor C3, which is previously disconnected from the collector of the transistor T2, voltage is supplied to the amplifier input from the sound generator (0.2 V, frequency 1000 Hz).

The feedback loop at point "b" must be broken. The control of the output voltage waveform is observed using an oscilloscope connected in parallel with the loudspeaker. If large "steps" are observed at the junctions of the half-waves, you need to clarify the value of the resistor R19.

It is selected according to the minimum distortion, which almost completely disappears when the feedback loop is turned on. The establishment of other cascades does not differ in any features. In cases where a sensitivity of about 250 mV is required from the amplifier, the first two stages on transistors T1, T2 can be excluded from the circuit.