Combating the 250V peak when turning off the relay

A project log for Muffsy Stereo Relay Input Selector

Open Source, versatile audio relay input selector controlled by an ESP32

skrodahlskrodahl 05/25/2018 at 08:010 Comments

I just found this video that shows very clearly why the diodes on the relays are needed. Worst case, you'll get a 250V peak without them. This can harm your electronics, and will create very audible pops.

The Muffsy Relay Input Selector combats this by using the flyback diodes, of course, and separating the power and signal grounds.