Resister value calulation

[Mr KAR]

Hi in my design i am using 24 volt 8 amps relay.I that circuit to check the relay status iplan to add one led. I want to know that value of that rsister and how to calculate.

Can anyone help to solve this issue.

 

[birdman0_o]

[24V - (2 to 3 V)]/20mA = Resistor.
Where do you plan on putting the led, will it be a basic on/off indicator?

 

[Mr KAR]

thanks i want to check relay is active or not so that i plan to add led.

yes basic on/off indicator

 

[birdman0_o]

Yea what I said will work. Just put it in parallel with the other circuitry the relay is turning on.

 

[Mr KAR]

Thanks. I choose Forward volt 2.3v. So your Calculation shows 1.1k.

 

[birdman0_o]

The foward voltage will depend on your specific led, you can find it in the datasheet. 1.1K sounds right for the value you have chosen.

 

[Mr KAR]

ya thanks in my datasheet shows forward voltage 2.3.

Thanks for youe help

 

[crutschow]

Yea what I said will work. Just put it in parallel with the other circuitry the relay is turning on.

If you put the LED and resistor across the relay coil instead of the contact load, you can have any value of voltage or type (AC or DC) on the relay contacts without it affecting the LED circuit operation.

 

[birdman0_o]

I can't picture this Carl, do you have a schematic handy?

 

[Mr KAR]

Relay contact rating is 8A @ 250VAC/30VDC(NO):8A @ 250VAC; 4A @ 30VDC(NC)

I don't have any schematic.