Use of light-dependent-resistor circuit to remotely reset digital constancy meter
Alexander Perec, Hideo Kubo · International Journal of Radiation Oncology*Biology*Physics · 1990
A digital constancy meter which has been used in our institution uses a plane-parallel chamber for daily morning output checks of treatment machines. After exposure, the user has to enter the treatment room to obtain the charge reading and reset the meter for the next reading. To avoid this extra step and save time, a remote reset circuit which includes a light-dependent-resistor (LDR), was built into the meter. When the room light is turned off (or dimmed) from the console, the light-dependent-resistor will trigger a circuit which will reset the meter.