SU949555A1 - Device for measuring non-uniformity of transistor current transfer coefficient - Google Patents

Description

This invention relates to. Measure. telnoy technology and can be used in the control of the transistor in the process of their production.

A device for measuring the dependence of the current transfer ratio of a transistor on a collector current, comprising a sweep, a low frequency generator, a controlled transistor, a collector resistor, the voltage from which is fed to the horizontal plates of an oscilloscope, as well as a transformer, a high-pass filter, amplifier and detector, voltage, is known. from the output of which is fed the vertical plates of the oscilloscope l.

However, this device has a low measurement accuracy.

The closest technical solution to the invention is a device for measuring the current transfer coefficient of transistors, comprising a low frequency current generator, a contact device for connecting a measuring transistor, an emitter current regulator, a collector charging stabilizer, and a protection unit. indications, amplifier, ratio meter and t2l meter.

However, the known device is unsuitable for measuring the non-uniformity of the current transfer coefficient in mass production conditions. transistors due to poor performance measurements, since. in it, the non-uniformity of the current transfer ratio is determined by the ratio of the maximum transfer coefficient of the current of the transistors in a given dynamic range of the emitter current to the value of this parameter at a fixed value of this current. To determine it, the maximum value of the current transfer ratio of this transistor is measured, the current through it is smoothly changed, and the non-uniformity of the current transfer ratio of the transistor is calculated from the ratio of two current transfer ratio values;

The purpose of the invention is to increase the measurement speed.

The goal is achieved by the fact that the device for measuring unequal.

25 of the number of current transfer coefficient of the transistors, containing a ratio meter, the output of which is connected to the measuring device, a low-frequency current generator connected

30 through an isolating capacitor to a terminal for connecting an emitter, a transistor under test, a collector voltage source connected to a terminal for connecting the collector of a transistor under test} and through a blocking capacitor by ground bus to which the first terminal of the current collector is connected, the second terminal of which is connected to terminal to connect the base of the test transistor and the amplifier input, a rising current generator, peak detector, detector, shred, additional collector resistor and comparator, n The first output of the rising current generator is connected to the terminal for connecting the emitter of the test transistor, the second output is connected to the comparator input and the first output of the additional current collecting resistor, the second output of which is connected to the ground bus, the comparator output is connected to the control input of the key, the signal input which is connected to the output of the amplifier and the input of the peak brush, and the output is connected to the input of the detector, the output of which is connected to the first input of the ratio meter, VTO.ROY which input is connected to the output Ikov detector. FIG. 1 shows a block diagram of the proposed device; in FIG. 2 is a graph of current transfer ratio versus emitter current; in fig. 3 — voltage and current diagrams at the outputs of the main device nodes. The device contains a low-frequency current generator 1 connected via an isolating capacitor 2 to the emitter terminal 3 of the test transistor, to which is also connected the output of the rising current generator 4, grounded through the collector resistor 5. The collector voltage of the controlled transistor 7 is connected to terminal 6 of the transistor. blocking capacitor 8, through which the collector of the transistor is grounded in alternating current. Terminal 9 of the base of the tested transistor is grounded to through the collector resistor 10, sig After amplification in amplifier 11, the signal is supplied through switch 12 and detector 13 to the input of the ratio meter 14, and through the peak detector 15 to the second input of the ratio meter, at the output of which the measuring instrument 16 is turned on. The control input of the switch 12 is connected to the collector resistor 5 in the circuit of the generator 4 of the increasing current through the comparator 17. The device operates as follows. From the low-frequency current generator 1 to the emitter of the controlled transistor, a low-frequency current is set. The constant current transistor modes are set using the collector voltage source 7 and generator 4 of the current increase in the emitter circuit. The amplitude of the alternating signal in the emitter circuit of the monitored transistor is constant (Fig. Za), and in the base circuit it changes (Fig. ZB) depending on the magnitude of the transfer coefficient, which varies with the constant emitter current of the monitored transistor (Fig. 3c) . The alternating signal from the current collector resistor 10 in the base circuit of the monitored transistor after amplification goes to the peak detector 15 and through the key 12 to the detector 13. The key 12 is controlled by a comparator 17, which, when DC current reaches the emitter circuit, is triggered (Fig. 3g ), closing the key 12 (Fig. 3a), and the output of the detector 13 is memorized, for example, 5kenie U, proportional to the value of the alternating current base, corresponding to the value of the direct current of the emitter 3 (Fig. 36). With a further increase in the direct current of the emitter, the drive coefficient of the transistor increases and, with a base current value of L, the gain reaches its maximum value and then begins to decrease (Fig. 2). The value of the alternating current of the base of the transistor corresponding to the maximum value of the gain factor is stored at the output of the peak detector 15 in the form of a constant voltage Utj proportional to this current (Fig.). The unevenness of the current transfer ratio of the transistor K is determined by the ratio V htieMdKb l - gchemin. The maximum and minimum values of the current transfer ratio of the transistor are respectively equal. i Nemax., i alternating current in the emitter circuit} alternating currents in the circuit L, d of the base, corresponding to the minimum and maximum values (1) taking into account (2), a. also based on the ratio of 0 0 (especially with the 3 corresponding .. receiving a- (e max 4ieMMH

Since the voltages and / (Figs. 3b and 2), proportional to the currents 0 and, are respectively fed into the channel of the numerator and the denominator channel of the ratio meter 14, the meter 16 provides direct readings of the magnitude of the current transfer coefficient of the monitored transistor

The use of the invention in linear transistor meters and classifiers significantly improves the performance of the control of transistors by the magnitude of the non-uniformity of the current transfer coefficient of the transistors.

Claims (2)

The invention The device for measuring the non-uniformity of the current transfer coefficient of transistors, comprising a ratio meter, the output of which is connected to a measuring device, a low-frequency current generator connected via an isolating capacitor to a terminal for connecting an emitter of a test transistor, a collector voltage source connected to a terminal for connecting a collector of the transistor under test .and through a blocking capacitor with a ground bus to which the first current collector pin is connected istora whose second pin is connected to A terminal for connecting the base of the test transistor and an amplifier input, characterized in that, in order to speed up the measurement process, a rising current generator, a peak detector, a detector, a key, an additional collector resistor and a comparator are inserted in it, the first output of the rising current generator is connected to the terminal to connect the emitter of the test transistor, the second output is to the input of the comparator and the first output of the additional current-collecting resistor, the second output of which is connected to the ground bus, the output of the comparators torus connected to the control input of the key signal input coupled to, the output of the amplifier and the input of the peak detector and an output connected to the input of the detector, whose output is connected 0 with the first input of the ratio meter, the second input of which is connected to the stt, the peak detector path. Information sources, 25 taken into account during the examination 1. Stolsky E. Measurements of transistor parameters. M., Soviet Radio, 1976, p. 213-215, fig. 92 2. Collection. Electronic strength, 1979, vol. 6, s. 59 and 60, fig. 2 (prototype). ,