auto-sensing voltage switch

[440roadrunner]

I need to find or design a circuit that detects the input line voltage (i
will be either 110vac or 24vac), and then toggle a switch (or relay) t
the output path to the proper circuit.

The logic of the circuit would be something like:

If line-in voltage is 110v then switch position A
If line-in voltage is 24v then switch position B

Unit should handle 2amp max current draw.

Is anything like this commercially available?
If not, any ideas?

I know this is probably something quite simple for you guys...

Thanks!

 

[ehsjr]

I need to find or design a circuit that detects the input line voltage (it
will be either 110vac or 24vac), and then toggle a switch (or relay) to
the output path to the proper circuit.

The logic of the circuit would be something like:

If line-in voltage is 110v then switch position A
If line-in voltage is 24v then switch position B

Unit should handle 2amp max current draw.

Is anything like this commercially available?
If not, any ideas?

I know this is probably something quite simple for you guys...

Thanks!

It's a 120 VAC relay. When 24 VAC is applied to its coil,
nothing happens, and the relay stays de-energized. When
120 VAC is applied to its coil, the relay is energized,
and the contacts transfer.

+------Normally Open
|
| +------ Common
| |
o o o------ Normally Closed
----- | | |
Vin ------|Relay| | | |
------|Coil | |> |<-+
-----

Shown de-energized. A path for current exists from Common
to Normally Closed. When energized, that path is opened,
and a new path is created from Common to Normally Open.

You can see such a relay at
http://www.allelectronics.com/
Put RLY-453 in the search box. That particular relay
has two sets of contacts, and the contacts can handle
12 amps.

Ed

 

[Rich Grise]

It's a 120 VAC relay. When 24 VAC is applied to its coil,
nothing happens, and the relay stays de-energized. When
120 VAC is applied to its coil, the relay is energized,
and the contacts transfer.

+------Normally Open
|
| +------ Common
| |
o o o------ Normally Closed
----- | | |
Vin ------|Relay| | | |
------|Coil | |> |<-+
-----

Shown de-energized. A path for current exists from Common
to Normally Closed. When energized, that path is opened,
and a new path is created from Common to Normally Open.

You can see such a relay at
http://www.allelectronics.com/
Put RLY-453 in the search box. That particular relay
has two sets of contacts, and the contacts can handle
12 amps.

I saw a guy do this to switch from 120V to 240V mains, but
he added a diode and a cap for some reason, and every time
I plugged one in to 240 to test, I kinda cringed expecting
an explosion. It did seem to work OK, however.

Cheers!
Rich

 

[Pooh Bear]

I need to find or design a circuit that detects the input line voltage (it
will be either 110vac or 24vac), and then toggle a switch (or relay) to
the output path to the proper circuit.

The logic of the circuit would be something like:

If line-in voltage is 110v then switch position A
If line-in voltage is 24v then switch position B

Unit should handle 2amp max current draw.

Is anything like this commercially available?
If not, any ideas?

I know this is probably something quite simple for you guys...

SGS-Thomson once made an IC specifically to do this ( except it was 120/240V
). One important thing to note is that the status needs to be latched once
detected or you may get a loud band under brown-out recovery conditions !

http://www.datasheetcatalog.com/datasheets_pdf/A/V/S/0/AVS08CB.shtml

Graham

 

[Jasen Betts]

SGS-Thomson once made an IC specifically to do this ( except it was 120/240V
). One important thing to note is that the status needs to be latched once
detected or you may get a loud band under brown-out recovery conditions !

~~~~~~~~~~~
like Deep Purple -


Smoke Upon the Water


(sorry)

Bye.
Jasen