i have circuit schematic with uses a 555 timer powered at 12V to operate a relay.
I want to change the switch for my amp but this switch is rated @1A max so i cannot use directly because the amp draw almost 5 amps from mains, but if I use the circuit iìm a little confuse by the relay, i never worked with relays before.

I see that relays are given in catalogs with voltage coil specification and contacts max current something like 12V/2A.

My circuit is powered by a 12 VDC supply so relay coil must be 12V. Can it be higher voltage level, say 24V? On the other hand if contacts are 10 A rated current can i use mains live and neutral if relay is DPDT?

I want to be sure before building this circuit, not to burn the whole project

Tommorrow i'll post the schematic, it has also 2 LED's to indicate on/off status

 

Relays have two parts, the coil part and the switch part.

The coil part usually has a coil resistance, a voltage to turn on, and a current to turn on spec. That's what's needed to activate the coil. Don't go too high on current/voltage or you'll overheat/destroy the coil. If the voltage you supply is too low, it will fail to activate - don't get one that's not what you want.

The contact part is rated just like any other switch. Don't exceed any of those parameters either. Also make sure you check AC/DC specs as well as motor specs, they're special cases that could cause more wear/damage to the contacts than normal. Typically DC and motor specs are much more pessimistic.

So what you need is input coil 12V, 100mA or less (though a 555 probably can drive more, better to be safer), and contacts of 220VAC, 5A per contact/circuit or higher. Adding a bit more margin would be nice too. You can use a DPDT to switch both hot and neutral for more safety, if you want, just don't miswire. You could also use two DP contacts in parallel to provide more margin, too.

 

Here is the diagram


I have a DPDT, (just to hook both live and neutral) relay rated @ 12V coil / 10A but those 10A is for AC or DC? I can use to switch for AC current? It is not specified voltage contacts only current

 

if a voltage is not specified, likely it's a low voltage DC relay and you shouldn't use it. You may get arc-over as the dielectric in the relay if it's not strong enough to handle 220VAC.

 

Do you have a part number for this relay?
Who made it?
Can you send a picture?

 

Yes, here is the link, this relay i want to use, DPCO plug-in relay, coil is rated @12VDC and contacts @15A-220V, i think is a very good choice for schematic above, what do u think?

If circuit is powered @ 12VDC also the relay must be rated @12VDC coil, right?

Thx, for any help

 

Where do you live?

As there are different shops in different parts of the world and you haven't filled your location in we can't really help you.

I would look in RS components or Farnell.

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I live in Romania, and first shop to buy from is Farnell, that link above is the online catalog from Farnell UK