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Zero Voltage Switch Test Circuit

IP.com Disclosure Number: IPCOM000083894D
Original Publication Date: 1975-Aug-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Radcliffe, WE: AUTHOR

Abstract

The test circuit depicted in the drawing measures the amplitude of the output current pulse of a zero-voltage switch module. The output current pulses from this module vary in width from 30 to 270 usec and in amplitude from 30 mA to 420 mA, depending on the frequency (50-60 Hz) and amplitude (138 to 374 volts peak) of the input signal. Also there are two other variables, as follows: 1) The output pulse placement, around the zero crossing of the input, varies from module-to-module, and with the above input changes. 2) The output pulse amplitude has two different values, one for a positive going input and one for a negative going input pulse.

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Zero Voltage Switch Test Circuit

The test circuit depicted in the drawing measures the amplitude of the output current pulse of a zero-voltage switch module. The output current pulses from this module vary in width from 30 to 270 usec and in amplitude from 30 mA to 420 mA, depending on the frequency (50-60 Hz) and amplitude (138 to 374 volts peak) of the input signal. Also there are two other variables, as follows:
1) The output pulse placement, around the zero crossing of

the input, varies from module-to-module, and with the above

input changes.
2) The output pulse amplitude has two different values, one

for a positive going input and one for a negative going

input pulse.

The test circuit measures the output current (output voltage divided by RL) 30 usec. after the start of the output pulse and, in two tests (controlled by relay K1) looks at the output pulse, generated by a negative going input or a positive going input signal.

The operation of the circuit is as follows:

With the AC input 1 applied and with relay K1 in the normal position, the timing is as shown. The output 5 of comparator A1 has the same timing as the output of the device under test (D.U.T.) and generates a fixed amplitude pulse as the output of the D.U.T. varies. The output 3 of comparator A2 is a negative going pulse, at t0. This signal generates a 4.8 msec pulse 4. Signals 4 and 5 are ANDed together, such that the leading edge of the output of A1 generates signal 6. Signal 6 is the strobe fo...