Need help with switch...110v and 12v.

[matt7738]

I think I'm asking this the right way......What kind of switch works on 110v and switches a 12v circuit?

My project involves using a security light with a photocell. My plan is to use the on/off status of the light bulb. The wires going to the socket will be connected to the switch. I'll use that to open or close a 12v circuit. The 12v circuit is independently energized.

Basically, if 110v is present, switch is closed and 12v flows. If 110v is absent, the 12v circuit is open.

Is a switch like this reasonable?

The alternative I've come up with is to use the bulb socket to energize a power strip(or socket) with a 12v power supply plugged into it. I'd rather keep the number of transitions to a minimum and keep it neat. I'd also rather not solder resisters, capacitors, and what have you.

Any help is appreciated.

 

[Arouse1973]

Hello
What about a relay?
Thanks
Adam

 

[matt7738]

Hello
What about a relay?
Thanks
Adam

I'm ok with a relay. My biggest trouble with this is that I am not familiar with electronics. I understand basics, but don't know the correct terminology for some things.

I've tried using "110v 12v5a relay" in searches, but I think I'm using incorrect names or labels. What would be the correct part nomenclature for this kind of relay?

Thanks for your help.

 

[Arouse1973]

110 V relay. Then look for one that the contacts are rated for a current of 5 Amps.
Adam

 

[Arouse1973]

Like this
http://www.meteorelectrical.com/110...untry_id=222&gclid=CP7EgOnlzcMCFSbkwgodv54AdQ#

 

[Jouellet]

Ebay will also get you one for 3.50$US, shipped....

 

[hevans1944]

Make sure the relay coil is rated for 110 VAC (NOT DC!) and the contacts are current- rated for whatever 12 VDC load you want to switch. Wire the relay coil in parallel with the lamp so the relay energizes when the lamp is on. Use normally-open contacts on the relay to switch your 12 VDC power.

You can purchase relays with mating sockets that have screw-terminals. No soldering necessary. Google "relays with 110 V AC coils and screw-terminal relay sockets".

 

[matt7738]

Make sure the relay coil is rated for 110 VAC (NOT DC!) and the contacts are current- rated for whatever 12 VDC load you want to switch. Wire the relay coil in parallel with the lamp so the relay energizes when the lamp is on. Use normally-open contacts on the relay to switch your 12 VDC power.

You can purchase relays with mating sockets that have screw-terminals. No soldering necessary. Google "relays with 110 V AC coils and screw-terminal relay sockets".

Thanks. I had thought about the normally open/closed thing a little and keep going back and forth until I do a layout. I have a 50/50 chance of getting it right. Since it is a DC control signal, I think I can just switch the wires to get what is needed.

 

[hevans1944]

Most relays come with either Form A or Form C contacts. Form A contacts are a single pair of contacts that are either normally open or normally closed when the relay coil is NOT energized. From your description, you would want a normally open Form A contact. Form C contacts offer BOTH a normally open AND a normally closed set of contacts connected to a common contact. You can pick which one you want to use to switch your 12 V DC circuit, so Form C contacts are more versatile.