Hi all,

I'm using a "big" 220V relays rated 10A with 3 contacts to switch a light DC load ON when line power goes off. 1 contact will fit my need, but they are available for about 3.5$ while the price of the 3 contact 220V relay I'm using is about 1$ only. Both are rated 6 to 10A. The load I'm using draws a current about 150mA or so... which make using such relays "odd" to use for operating them.

I'm building things using this load that should operate when AC power goes off.
So I think there should be a simpler way to do it.. maybe using a triac?

regards,
Hazim

 

What is the voltage and current of the DC Load?

Until you have a thorough understanding of what you are working with, I'd suggest staying with the relay setup. Triacs typically are for controlling AC waveforms, while SCRs are typically for DC (both are called "Thyristors" though).

Read the e-book, accessible through the bar along the top of the screen to get more comfortable with what you are trying to do.

 

I've already read the e-book and read about thyristors. I know that SCRs can be switched on but not off when the gate signal goes off... if it works like that, it doesn't work..
I said that the current of the load is 1bout 150mA, the voltage is 12VDC.

Regards,
Hazim

 

Relay is the simplest way.

 

If your control signal is 220VAC, then a contactor (relay) is the standard choice. If you are working with HVDC, then a voltage divider can be used to control a MOSFET to switch the LVDC load.

 

So I think there should be a simpler way to do it..

if it already works and only costs $1, how simplier can it get?

 

if it already works and only costs $1, how simplier can it get?

It's not logical to use a relay rated 10A with 3 contacts to switch a 150mA DC load... It's not a problem for me but there should be a more appropriate way to to that.

 

one man's logic is another man's insanity.

 

Use a smaller 220V relay.

 

As you can get 1/8, 1/4, 1/2, 1, 2, 3, 5, 10, 20W and more resistors, and 6.3, 10, 16, 25, 36, 50, 63, 100V and more capacitors.. and more ratings for parts... it's better to use appropriated rated components... it's the same for that relay.. Anyway, I'll continue using the relay, the relay with 3 contacts which costs about 1$ where the smaller ones costs more, Bill.

Regards,
Hazim