I am trying to use a simple 18v DV triggered Relay in Multisim. The probem is that I need the relay to trigger even when the DC polarity is reversed. Seems that every relay I try in Multisim only works with a DC power source hooked up one way, if you revese it nothing happens.

 

You can add a diode bridge to the relay coil (positive bridge output to plus coil input). The bridge will rectify the voltage so either input polarity will operate the relay.

Alternately you could use two relays with their contacts in parallel and the coils wired with opposite polarity to your source.

 

You can add a diode bridge to the relay coil (positive bridge output to plus coil input). The bridge will rectify the voltage so either input polarity will operate the relay.

Alternately you could use two relays with their contacts in parallel and the coils wired with opposite polarity to your source.

I was able to make a diode bridge and it does sort of work. I can energize the coil with either polarity now. But when I take power away from the coil Multisim keeps giving me an error now. Seems like Multisim is too tuchy for simple mechanical type sims, I keep getting all kinds of errors tring to use relays.

 

Trying adding a resistor across the relay coil to see if that helps.

 

Trying adding a resistor across the relay coil to see if that helps.

I changed the resistance on the coil of the relay and it seems to be working for now. Thanks for the help.