MEASURING APPARATUS

PROBLEM TO BE SOLVED: To obtain a measuring apparatus which prevents the synchronization deviation between a synchronizing signal for measurement and a voltage to be measured, by installing a square-wave-voltage generation circuit which generates a square-wave voltage synchronized with the output of a reference sine-wave oscillator and which sends the voltage to a measuring part as a synchronization control signal. SOLUTION: The output voltage Vosc of a reference sine-wave oscillator 1 is applied to an AC constant-current generation circuit 2 and to a square-wave-voltage generation circuit 5. A constant current Iout which is sent out from the AC constant-current generation circuit 2 flows to a load resistance Rl as an object to be measured, a voltage Vm which is generated across both ends of the resistance Rl is measured by a measuring part 3, and the value of the resistance Rl is computed. The square-wave voltage generation circuit 5 is constituted of a comparator 6, it generates, from the output voltage Vout of the oscillator 1, a square-wave synchronization signal Vs for measurement, which is synchronized with the output voltage Vosc . When a phase is changed in the output voltage Vosc of the oscillator 1, the phase of the synchronizing signal Vs for measurement, from the square-wave-voltage generation circuit 5 is changed so as to follow its change, and a phase shift is not generated between it and the voltage Vm to be measured.