More  Relay Circuits

Computer Controlled Power Relay -- July 31, 2011

Often there is a need to turn on and off a 120vac device using a low power +5v logic signal from a computer.  The circuit below shows how this could be done.  The circuit uses a power relay with a 120vac coil and 10 Amp contacts.  A small solid state relay turns on and off the relay.  The solid state relay provides 5KV isolation from the computer.