Do both of the LEDs in the OC-100 family have to be working in order to get an output from the photo diode? by Voltage Multipliers Inc. | Jul 5, 2018 A Do both of the LEDs in the OC-100 family have to be working in order to get an output from the photo diode? No, but the output (Ir) of the photo diode is decreased by one half if only one LED is working. Back to Top