ELECTRICAL CHOPPED FREQUENCY CIRCUIT FOR CHARACTERIZING PYROELECTIR SENSOR

Abstract

In this work an electrical chopped frequency circuit was designed and fabricated to characterize pyroelectric sensor. The proposed device is composed of chopping system which includes an Arduino® board programmed through the computer to generate multiple wavelengths, transmitting circuit to convert the wavelengths generated to infrared signal with the range of chopped frequency, sensor with amplification circuit, and signal conditioning like oscilloscope or voltmeter. The proposed measurement circuit was tested and evaluated for polyvinyldene difluoride sensor at room temperature with changing the frequency range from 0.01 Hz to 100 Hz. The voltage responsivity, noise equivalent power (NEP) and detectivity of polyvinyldene difluoride (PVDF) pyroelectric sensor was tested and measured in the range from 0.01 Hz to 100 Hz. The voltage responsivity of PVDF pyroelectric sensor was found to be 117 V/W at 0.5 Hz, NEP was about 4.42×10-7 W/Hz1/2 at 100 Hz and the detectivity was equal to 1.12×106 cmHz1/2/W at 100 Hz.