SU1238005A1 - Curve tracer - Google Patents

Abstract

The invention relates to the field of automation and measurement technology. The purpose of the invention is to expand the functionality. The device contains a generator 1, terminals 2, 3 and, 7 for connecting the transistor under study, an oscilloscope 5 ,. sweep generator 6, potentiometer 8 to switch 9. Introduction to the device of potentiometer 8 and switch 9, made in the form of an electronic switch on a transistor and a self-oscillating multivibrator, makes it possible to observe static and load characteristics simultaneously on the oscilloscope screen. In addition, the graduation of the axes on the screen of the x-ray scanner is performed, and the temperograph allows determining not only static, but also dynamic parameters of the transistor. 3 il. (L with:

Description

I 1

The invention relates to automation and measurement technology and can be used to study the characteristics of transistors.

The purpose of the invention is to expand the functionality by ensuring the removal of the family of characteristics of the semiconductor devices under study, i.e. in the static and load mode of the investigated transistor.

Figure 1 presents the block diagram of the proposed device; figure 2 - block diagram of the switch modes of the transistor; Fig. 3 shows time diagrams, according to the work of the characterographer.

The characteristic graph (FIG. 1) contains a 1-stage voltage generator, the first output of which is connected to terminal 2 for connecting the base of the transistor under investigation, a terminal 3 for connecting the emitter of which is connected to the second output of the 1-stage voltage generator 1, common busbar, first output of resistor 4 and the first input of the oscilloscope 5, the second input of which is connected to the second output of the resistor 4 and the first output of the sweep generator 6, the third input of the oscilloscope is connected to terminal 7 for connecting the collector of the test transistor, potentiometer 8, switch 9, made in the form (Fig.2) of an electronic key on transistor 10, and self-oscillating multivibrator 11, the input of the self-oscillating multivibrator 11 connected to the first output of the resistor 4, and the first output to the base of the transistor 10, the emitter of which connected to the second output of the self-oscillating multivibrator 11, the terminal 7 connecting the collector of the test transistor and the first terminal of the potentiometer 8, the second pin of which is connected to the second output of the sweep generator 6 and the switch transistor key 10. The second input of the oscilloscope 5 is connected by its vertical deflection plates, and the third input is connected to the horizontal deflection plates of the oscilloscope 5.

The operation of the device is as follows.

Example. Study of the output characteristics of a bipolar transistor in a common emitter circuit

38005

(figure 1). The test transistor is connected to the appropriate terminals for connecting the emitter, collector and base of the test transistor. If switch 9 is bypassing resistor 8 (load impedance Ец), the sweep voltage from sweep generator 6 is fed directly to the collector of the transistor 10 being investigated and simultaneously to the third input of the oscilloscope 5. The sweep voltage form is not significant, as it affects only waveform uniformity.

15 Therefore, in the sweep generator 6, pulses can be used, which are possible within the network voltage, and both the forward and reverse oscilloscope beam 5 can be used. When changing

20 of the collector voltage, which is provided by the sweep generator 6, and the direct current of the base of the transistor under investigation, respectively, the collector current varies. In the collector

The 2S circuit of the investigated transistor BKJHO is a resistor 4, the resistance R of which is much less than the output resistance of the investigated transistor (for example, R 100 Ohms), the voltage drop on which is proportional to the collector current. Applying this voltage to the second input of the oscilloscope 5, get an oscillogram of one of you. best static response

j of the transistor under study. If with each sweep stroke (forward or reverse) to provide a constant base current value, but a different current value (in steps) with each test loop, a family of static output characteristics of the transistor under study is obtained. A stepped base current is provided by a 1-step voltage generator. The synchronization of the generators 1 and 6 is carried out by the mains voltage. Timing diagrams (fig. 3, left half) show the voltage U, of the network, the voltage of the codec Q, the stepped base current, the voltage J U on the measuring resistor 4 in the study of static characteristics when the load resistance R (potentiometer 8) shunted by switch 9.

55 To study the load characteristic, the switch 9 connects the load resistance R (potentiometer 8) to the collector circuit, and the sweep voltage from the sweep generator 6 is supplied to the collector of the transistor under investigation through a potentiometer 8. At the same time, the voltage on the collector and the collector current change in accordance with the load characteristic of the transistor under study, i.e. taking into account the connected resistance of the potentiometer 8. The base current, as before, is stepwise. The time diagrams (Fig. 3, right half) show the nature of the change of the same currents and voltages of the device when studying the load characteristics. The stress-waveform is a type of shortened static characteristic. Each of the characteristics is shortened by an appropriate amount of voltage drop across the resistance of the potentiometer 8, and the limitation itself is highlighted on the screen highlighted by a dot. When the resistance of the potentiometer 8 changes, the location of the points of limitation changes, and hence the inclination of the straight line connecting these points. Switch 9 periodically connects or shunts potentiometer 8 with a switching period equal to the period of the 1-stage voltage generator. The last condition is satisfied by the synchronization of the generator 1 of the switch 9 and the generator 6 with the same mains voltage. At the same time, static and load characteristics are periodically displayed on the oscilloscope screen. Using the highlight effect, these characteristics are observed simultaneously.

Thus, the additionally introduced elements expand the functional capabilities of the characterograph, which consist in the possibility of simultaneous observation on the oscilloscope screen of static and load characteristics. In addition, the proposed characterizer allows to determine not only static, but also dynamic parameters of transistors by calibrating the axes on the oscilloscope screen.

Formula of the sample

A characteristic graph containing a step voltage generator, the first output of which is connected to a terminal for connecting the base of the transistor under study, a terminal for connecting the emitter of which is connected respectively to the second output of a step voltage generator, a common bus, the first output of the resistor and the first input of the oscilloscope, the second input of which is connected to the second output of the resistor and the first output of the sweep generator, the third input of the oscilloscope is connected to the terminal for connecting the collector of the transistor under study, lichayuschiys in that, in order to expand functionality. capabilities, it is equipped with a potentiometer and a switch made in the form of an electronic switch on a transistor and a self-oscillating multivibrator, the input of which is connected to the first output of a resistor, and the first output of an oscillatory multivibrator is connected to the base of the transistor, the emitter of which is connected to the second output of an oscillatory multivibrator, terminal for connecting a collector the investigated transistor and the first output of the Potentiometer, the second output of which is connected to the second output of the sweep generator and the collector in the transistor switch.

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Compiled by T.Ivanova Editor S.Lisina Tehred L.Oleinik Proofreader A.Obruchar

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VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., Du / 5

lt

Production and printing company, Uzhgorod, Projecto st., 4

FIG. 3

Claims (1)

Claim A characterograph containing a step voltage generator, the first output of which is connected to the terminal base for the studied transistor, the emitter terminal of which is connected respectively to the second output of the step voltage generator, a common bus, the first output of the resistor and the first input of the oscilloscope, the second input of which is connected to the second output of the resistor and the first output of the sweep generator, the third input of the oscilloscope is connected to the terminal for connecting the collector of the studied transistor, o characterized in that, in order to expand the functionality, it is equipped with a potentiometer and a switch made in the form of an electronic key on a transistor and a self-oscillating multivibrator, the input of which is connected to the first output of the resistor, and the first output of the self-oscillating multivibrator is connected to the base of the transistor, the emitter of which is connected to the second output of the self-oscillating multivibrator, the terminal for connecting the collector of the investigated transistor and the first output of the Potentiometer, the second output of which I will Connect ene to the second output of the sweep generator, and the collector of the transistor switch.