GPO's relays and diodes .

arr2036 · Post by **arr2036** » Sat May 28, 2005 12:33 pm

Just wondering whether i needed a diode across the gpo in reverse , to protect the unit from back EMF when it's connected to a relay

. (I've done it already to be safe , just wondering whether i needed to ...

Tom · Post by **Tom** » Mon May 30, 2005 10:46 am

Hi arr2036,

It's always a good idea to use the diode in across the GPO when using a relay to protect the unit from back EMF.

Best Regards,

Tom · Post by **Tom** » Mon May 30, 2005 10:46 am

Hi arr2036,

It's always a good idea to use the diode in across the GPO when using a relay to protect the unit from back EMF.

If you have anymore questions or concerns, please feel free to post them.

Best Regards,

arr2036 · Post by **arr2036** » Wed Jun 07, 2006 2:32 am

Just to clear something up with this,

If you use physically switching electromagnetic relays, switching a 240v supply , you will almost certainly run into huge problems with the display. This is due to the emf radiation caused when the contacts are broken inside the relay.

The solution is to use a solid state relay, these will not need heat syncing if you get one with a higher enough rateing, and most will operate with a turn on voltage of 5-12v, and you don't even need a diode across it

.