SEMICONDUCTOR BRIGHTNESS DETECTOR Russian patent published in 1997 - IPC

FIELD: instruments, automatic control. SUBSTANCE: device converts capacitance to frequency using field-effect photo transistor as light- controlled capacitors for oscillating circuit. Passive coil is used as inductance element. This results in possibility of negative resistance at drain-to-drain terminals of transistors. This leads to oscillations in circuit which is produced by parallel connection of resistance element with capacitor characteristics to drain-to-drain terminals of transistors and inductance resistance of passive coil. When light enters field-effect photo transistors, capacitance constituent of total resistance at drain-to-drain terminals is altered, so that resonant frequency of circuit is changed. EFFECT: increased functional capabilities. 1 dwg