Nagative DC and Relay

[guavatone]

Can I use the Negative voltage supply of -24v to triger a delay by reversing 0v and -24v?

Thanks in advance.

 

[CJ]

yes, in fact, many relays have a built in bridge so butt cleavage electricians can even handle it.

give em a Fluke and a tool belt and....... insta macho man!

Or matza man.

We do not discriminate.

 

[guavatone]

CJ you are nvts in a good way.....of course. ...er ....a ...bridge? I take it thats a yes on fooling the relay and the mooning electricians as well.

 

[CJ]

dc will flow thru the ac side of a bridge.
the bridge autmatically flips polarity.
sorry, Marinair varnish.

 

[guavatone]

What are you calling the bridge? the Diode? the Relay? I am a bit novice...

BTW i am using this setup.

 

[CJ]

bridge rectifier inside relay will flip 24 dc if you hook it backwards in most modern relays nowdays.

 

[guavatone]

Thanks, I had no idea they fit a bridge rect. in there. Sorry I didn't realize your abreviation. Funny how the bridge is not in the product diagram.

 

[PRR]

A standard DC relay does not care which way the polarity is.

I've never seen one with a Bridge rectifier either.

Some DC relays have a (single) built-in diode to suppress kick-back at turn-off. If so, they better have "+" and "-" marks on the coil, just match the polarity.

 

[FredForssell]

Some relays with + and minus terminals (like the Aromat TQ2) do not have internal diodes, but still require you use proper polarity. This is because of a small "helper" magnet inside the relay that allows the relay to be build with a smaller coil. With these relays, you still need to install an external suppression diode.