Abstract
This article describes the current-to-voltage converter for alternating current and its application to the alternating current electrometer.
The circuit is a 100% nagative feedback amplifier with a C-R coupling circuit incorporated at the input of a conventional impedance converter.
The time constant of the circuit becomes very large by the function of the negative feedback. Therefore, an alternating component in the DC signal current can be measured with the circuit down to an extremely low frequency.
For example, the equivalent time constant is about 12×104 seconds, when the coupling capacity is 5×10-9 farad, the resistance is 1010 ohms and the voltage gain is 2400.
In other words, the low cut-off frequency of the circuit is about 1.4×10-6Hz.
