Differentiation exposure meter circuit

Published:2011/4/29 4:54:00 Author:Nicole | Keyword: exposure meter | From:SeekIC

The sensitivity of BPX63 photodiode is 10mA/lx. This circuit can ensure the light and figure location only influenced by the useful light, and it will not beinfluenced by the noise singal. When it is used under gleam, this circuit can fast collect a series of short optical pulse. When the camera shutter is not opened, K1, K2 are closed, the operational amplifier output is connected to its inout terminal by FETT1. when it starts to expose, k1, K2 turn off, the circuit produce more than 3000 times enlargement ratio. Integral capacity C1 is charged by photocurrent, it makes the output voltage linear change with time. When the output voltage is 1V, T3's base-emitter junction starts to turn on. When C1 produces feedback by T3, RL is discontinuous flow, the exposure is ended. The power supply is ±3V.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Basic_Circuit/Differentiation_exposure_meter_circuit.html

Print this Page | Comments | Reading(3)