SU938220A1 - Device for measuring transistor current differential transmission coefficient - Google Patents

Description

one

This invention relates to technical physics and can be used in automated measurements of low signal parameters of low power transistors.

A device for measuring the differential current transfer ratio of transistors in a common emitter circuit is known, comprising a low-frequency generator, voltage sources, current generating resistors and two operational amplifiers 1.

The disadvantage of the known device is the inverse nonlinear scale of the meter, which reduces the measurement accuracy.

The closest in technical essence to the present invention is a device for measuring the Differential current transfer ratio of transistors, which contains a DC base source, a coupling capacitor and a current-supplying resistor of the base circuit, the subject

transistor, the control unit is constant the collector current, the collector voltage source, the collector circuit collector current, the collector circuit of the low frequency collector and the indicator 2,

A disadvantage of the known device is the change in the amplitude of the low-frequency component of the collector current within

10 measurement range, which causes additional errors due to the nonlinearity of amplifying and detecting devices included in the indicator.

15

The purpose of the invention is to improve the measurement accuracy and the expansion of the dynamic range.

This goal is achieved by the fact that the device for measuring differential

20 of the potential current transfer coefficient of the transistors, containing a DC source, the output of which is connected to the terminal for connecting the base of the tested transistor and the first output of the current-generating resistor, the second terminal of which is connected to the first face of the first coupling capacitor, the terminal for connecting the emitter connected to the common bus , a terminal for connecting a collector connected to the input of the DC control unit of the collector, one plate of the second coupling capacitor and the first terminal ohm current collector resistor, the second output of which is connected to the source of the collector voltage injected | Sieny trigger, integrator, modulator, voltage to frequency converter, pulse shaper, comparator and time meter, the trigger output through serially connected integrator and modulator connected With the second plate of the first coupling capacitor, the other output of the integrator is connected via a voltage to frequency converter w and the pulse shaper is connected to the control input of the modulator and ne vym input meter la temporal intervals, a second input coupled to an input trigger and the output pa komparatop whose input is connected to the other plate of the second separation condenser. The drawing shows a block diagram of a device for measuring the differential current transfer coefficient of transistors. The device contains a source of direct current (base), a coupling capacitor. 2 and the current-setting resistor 3 of the base circuit, the transistor k under test, the 5 unit of the constant current collector collector, the collector voltage source 6, the collector current collector 7 of the collector circuit, the separator capacitor 8 of the collector circuit, terminals 9 10, trigger P, integrator 12, converter 13 voltage to frequency, pulse driver, i15 modulator, time interval meter 16, comparator 17, terminal l8. The device works as follows. After the setting of the direct current mode, with the arrival of a short-time signal, the Start-up sets the voltage level at the integrator 12 code and the trigger 11 is set to the state at which the output voltage I + is at its output. This voltage is applied to the integrator 12, at the output of which a linearly varying voltage is obtained, (c) where c is constant; Ugjji (t) is supplied to the modulator 15. The voltage from the integrator 12 is also fed to the voltage-to-frequency converter 13, the output of which is a variable voltage with a linearly increasing frequency. From this voltage, using a pulse shaper 14, pulses are generated that control the modulator 15. The pulse repetition rate is determined by the expression V BblXW For a pulsed base current, you can write V (t) S 6btxU for a pulsed collector current) c ((ьr (v time t the small signal component of the collector current reaches the required value i, the comparator 17 trips the trigger 11 to the position where the output voltage is - and. At the same time, the pulse of the comparator 17 is fed to the meter 16 a, which by this signal measures the duration of the low-frequency oscillation period T .. Based on the expressions (2) and () can be written. Thus, the measured parameter is directly proportional to the pulse duration at the time of the achievement of the small signal component of the collector current required and, with appropriate calibration, it is determined by measuring the period. To ensure high measurement accuracy, it is necessary that the period of the pulse of the low-frequency component be changed from period to period. period was insignificant. The proposed device allows to increase the measurement accuracy (measurement error is ± 1, S% and expand the dynamic measurement range, as it provides a direct measurement scale at a post-day amplitude of the low-frequency component of the collector current, as well as increase productivity measurement process. Claims Device for measuring the differential current transfer coefficient of transistors, containing a DC source, the output of which is connected to the terminals to connect the base of the test transistor and the first output of the current-conducting resistor, the second output of which is connected to the first plate of the first coupling capacitor, the terminal for connecting the emitter connected to the common bus, the terminal for connecting the collector connected to the input of the DC control unit of the collector, one plate of the second coupling capacitor and the first output of the collector resistor, the second output of which is connected to a source of collector voltage, characterized in that To increase the accuracy of measurement and expansion of the dynamic range, a trigger, an integrator, a modulator, a voltage-to-frequency converter, a pulse shaper, a comparator, and a time interval meter are entered, the trigger output being connected through the serially connected integrator and modulator to the second plate of the first separator the capacitor, the other output of the integrator through a voltage converter - into the frequency and the forch worldizer of pulses is connected to the control input of the modulator and the First input of the measurement body time interval, the second input of which is connected to the trigger input and the output of the comparator, the input of which is connected to another plate of the second separation capacitor. Sources of information taken into account in the examination of T. Graham .. Measurement of parameters of transistors using circuits on an operational amplifier x.- Electronics, 1972, If 5, t. It5. 2. Aronov V.L., Fedotov Ya.A. Test and study of semiconductor devices. M. Higher School of Commerce, 1975.

Claims (1)

Claim A device for measuring the differential transmission coefficient 25 of the transistor current, containing a DC source whose output is connected to a terminal for connecting the base of the tested transistor and to the first output of a current-setting resistor, the second output of which is connected to the first plate of the first isolation capacitor, a terminal for connecting the emitter connected to the common bus, terminal for connecting the collector ₃₃ , connected to the input of the collector DC control unit, separate one lining of the second a capacitor and the first output of a collector resistor, the second output of which is connected to a collector voltage source, characterized in that, in order to improve the measurement accuracy and expand the dynamic range, a trigger, an integrator, a modulator, a voltage to frequency converter, a pulse shaper are introduced into it, a comparator and a time interval meter, the trigger output through a series-connected integrator and modulator connected to the second lining of the first isolation capacitor, another The integrator через s output through a voltage converter - to the frequency and the pulse fortifier is connected to. the control input of the modulator and the first input of the time interval meter, the second input of which is connected to the trigger input and the output of the comparator, the input of which is connected to another plate of the second isolation capacitor.