Isolation amplifier using light emitting diode

Abstract

An amplifier which optically transmits the current of voltage information using a light emitting diode(LED) is described. A modulator in the input and a demodulator in the output of the system compensate the nonlinearity of the LED. The linearity and the dynamic range of the input versus the output of the amplifier is investigated. The amplifier developed has a dynamic range of 60 dB( 10mV to 10V) and a nonlinearity which is within 0.1 percent of the full scale. The ground leakage current has been found to be 1.3 nA. The amplifier has been designed for the isolation of the nuclear instrumentation system (NIS).