SU817610A1 - Device for measuring resistor non-linearity - Google Patents

Description

The invention relates to electronic equipment and can be used in devices designed to control the linearity of resistors. - A device for measuring the nonlinearity of resistors is known, containing two sinusoidal voltage generators of different frequencies, a combinator level meter for G13. A disadvantage of the known device is that it can measure the nonlinearity of only those resistors that are asymmetric with respect to the origin of coordinates. ku The closest technical solution to the present invention is a device for measuring non-linearity of resistors, containing a source of voltage, a generator of two frequency voltages, the outputs of which are connected to the inputs of the blocking filter, the outputs of which are connected to the input terminals of the device for connecting the measured resistor which are also connected in series with a low-pass filter, a selective amplifier and f27 indicator. A disadvantage of the known technical solution is that they can measure the non-linearity of only those resistors that have a symmetric with respect to the origin of the coordinates, a characteristic, i.e. one that is described by a power polynomial containing terms with arguments only in an odd degree, while the volt-ampere characteristic of a real resistor can generally be described by a polynomial containing both terms with arguments in an odd degree and terms with arguments in even degree. The purpose of the invention is to expand the functionality of the device by allowing the measurement of the non-linearity of the resistors, with any volt-ampere characteristic. This goal is achieved in that a device for measuring the nonlinearity of resistors, containing an indicator, a dual-frequency voltage generator, the output of which is connected to the first input of the blocking filter, the outputs of which are connected to the input terminals of the device to which they are connected; and a selective amplifier, a generator of periodically varying voltages and a key phase unit are introduced, with the generator output of periodically varying voltages connected to the second swing buffer circuit and to one input of a phase unit key, a second input coupled to an output of the selective amplifier, and output - with an indicator.

Figure 1 presents the block diagram of the device; in fig. 2 - voltage diagrams.

The device contains input terminals for connecting the resistor 1 under study, blocking filter 2, generator 3 dual-frequency voltage, generator 4 periodically varying voltage, low-pass filter 5, selective amplifier 6, key phase unit 7, indicator 8

The device works as follows.

The resistor 1 under study is supplied with a dual-frequency oscillatory voltage (fig. 2a) from generator 3 and periodically varying, for example by harmonic law, voltage (fig. 26 from generator 4.). The voltage (see fig. 2b), acting on the investigated resistor 1, causes the appearance of the difference frequency (Fig. 2d) due to the nonlinearity of the investigated resistor 1. Generator 4 provides a voltage whose frequency is substantially less than the frequency difference of the generator 3.

The fencing filter, 2, does not pass a signal with a frequency equal to the frequency difference of the generator 3. The differential frequency voltage (Fig. 2d) generated due to the nonlinearity of the resistor 1 under study passes through a low-pass filter 5 to the input of the selective amplifier 6.

Low pass filter 5 and selective amplifier 6 must have sufficient bandwidth to transmit the differential frequency voltage (fig.2g) without distorting its envelope (figd), low pass filter 5 must pass oscillator 3 oscillation frequencies. the voltage applied to the key phase unit 7, controlled by the periodic voltage of the generator 4.

If the key phase unit 7 is open, the voltage (Fig. 2d) goes to the indicator 8, which measures the average value of this voltage. During the time the key phase unit 7 is open.

A measure of the nonlinearity of the resistor 1 is the voltage difference voltage level (fig.2g), averaged over the period of the oscillator frequency 4 relative to the supplied two-frequency generator voltage, the value of which is assumed to be known at a certain ratio c1 of the amplitudes of the dual-frequency (fig.2a) and periodic signal (fig. 26) constant frequency.

The opening time of the key phase unit 7 and the duration of the open state are controlled and determined by the purposes with which the nonlinearity of the resistors is measured.

To measure the level of non-linearity of resistors that have a symmetrical or asymmetric characteristic relative to the origin of coordinates, or those whose characteristics cannot be called symmetric or asymmetrical, it is necessary to open the key phase unit 7 for a time equal to the oscillation period of the generator 4.

If, when measuring nonlinear resistors, whose characteristic cannot be called even or odd, it is necessary to determine the total contribution to the nonlinearity given by the expansion members with even powers of arguments, the key phase unit 7 needs to be opened when the instantaneous value of the generator 4 is equal to zero ( Fig.26) and close it. after a time in which the instantaneous voltage of the generator 4 remains almost unchanged.

To determine the total contribution to nonlinearity from the decomposition terms with odd powers of the arguments of these resistors, the key phase unit 7 must be opened when the amplitude of the two-frequency voltage is equal (Fig. 2a) to the instantaneous value of the voltage of the generator 4 and close it after the voltage amplitude of the generator 4 is practically unchanged.

The use of the proposed device for measuring the nonlinearity of resistors significantly reduces the ingress of rejects into suitable products when sorting out operations to control the quality and reliability of resistors and also increases the productivity of the operation by measuring up to 7-10 pcs / s regardless of the type of the current-voltage characteristic of the resistors.

Claims (2)

1. Serdyuk G. B. and others. Structural methods for improving the accuracy, sensitivity and speed of measuring devices. II rep. scientific and technical conference Abstracts, Uman, 1975, issue 2, p. 62. 2. USSR author's certificate number 362260, cl. G 01 R 27 / Q8, 1971 (prototype).