What are the voltage and current ratings for both relays used in this circuit?

What is rating of both relay? I mean voltage, current etc.

Hi Ahmad

I found a link relating to relay rating., http://www.azatrax.com/relay-contacts.html

Hope it helps

There are 2 different parts of a relay and they have different ratings. Lets start with the coil which activates the relay. The coil is rated by how much voltage it takes to turn it on. Coils are also rated by what type of voltage ( AC or DC ) it takes to turn them on. So a coil rated at 120VAC means it takes 120 volts of AC power to turn them on.
The other rating a relay has is the rating of the contacts. This rating indicates how much current the contacts can handle and at what voltage. Lets say you have a relay that can handle 10 amps at 120VAC. This means you can flow up to 10 amps at 120 volt power. You can use the relay at lower voltage but not higher voltage. At higher than rated voltage you may burn the contacts, weld the contacts close, etc... No a good thing.

The relay datasheet should tell you what you need to know. For example this datasheet for the OMRON G5LE relay.

http://www.components.omron.com/components/we...6B03161CD86257538007424DB/$file/G5LE_0813.pdf

For the 12 volt, 450 mW *coil* the specs are:
rated current 33.3 mA
resistance 360 ohms
must operate voltage 75%
must release voltage 10%
max voltage 130% of rated voltage

These specs say do not exceed 15.6 volts and decrease the voltage to 1.2 volts to release the contacts.

Three of the *contact* ratings for a resistive load:
10 A at 120 VAC
8A at 30 VDC
Minimum load 100 mA at 5 V

The current rating higher at 120 VAC because contact arcing (during contact opening) extinguishes as the AC voltage crosses through zero. The minimum load is to prevent "dry switching" issues. With voltage and current that is too low the contacts can build up a resistive film over time. Sufficient voltage and current tends to reduce the build up of the resistive film.