| 摘要 |
PURPOSE:To confirm whether an IC to be tested operates normally in the same manner as a reference IC operates by confirming whether the same signals are outputted to the corresponding output terminals of the former IC and the latter IC by exclusive OR gates and light emitting diodes. CONSTITUTION:The output signal outputted to the 9th-15th terminals of the IC3 to be tested and the signal outputted to the corresponding 9th-15th terminals of the reference IC5 are inputted respectively to the exclusive OR gates 7-9-7-15. The gates 7-9-7-15 do not energize the corresponding light emitting diodes 8-9-8-15 and the light emitting diodes do not emit light when both output signals are made the same in the level. The corresponding gates 7-9-7-15 energize the diodes 8-9-8-15 and the diodes 8-9-8-15 emit light when both output signals are so formed as not to be coincident in the level. The IC3 to be tested is regarded to make the same operation as the reference IC5 if the output signals are applied to the gates at the level at which the diodes 8-9-8-15 do not emit light at all. The IC3 is thus discriminated to be normal. |
