4n25

Hi all, my first post, so please bear with me. I have some older 4N25 optocouplers, stamped QTC 4N25 0130K [the 0130K part is to be taken with caution as the font is very small and hard to read]; the other brand, which was purchased recently is stamped T EL 4N25 224. Strangely to me [an amateur]...

I designed this circuit to control a TCR (Thyristor Controlled Reactor) using two SCRs in antiparallel, which should be triggered through two MOC3021 drivers. To properly supply the MOCs and maintain isolation, I included a 4N25, whose function is to increase the voltage of the 3.3 V pulses and...

Hey all I have 6 buttons that have the following voltage: I want to hook up a 4N25 to each one of these so I can use the ESP32 as a "virtual push" to each of these buttons. When the button is pressed the 3.2vdc goes to ground. To minimize the amount of wire going to each one...