what can i use instead of relay

[nikhil arora]

I want to switch 20watt to 100watt light bulb one method is to use relay other method is to use SCR and i have heard of optically isolated SCR or triac will they work here my ac supply is 220V ac

 

[akg]

y don't...? remember the triggering

 

[nikhil arora]

yeah little bit of power electronics boring lectures
gate trigerring but what are safety precaution do i need a heat sink
and which scr or triac i must use

 

[Nigel Goodwin]

How about an SSR (Solid State Relay), this is essentially all the components required in one module, triac, opto-isolater, everything!.

 

[nikhil arora]

what is size of that and how much current it draws

 

[Nigel Goodwin]

what is size of that and how much current it draws

Depends on the specific one you use, but consumption is usually low.

 

[audioguru]

You didn't say dimming so why not switch the light with just a switch?

 

[Hayato]

You didn't say dimming so why not switch the light with just a switch?

I think he wants to do some automation.

Nikhil, you can use both, electromechanical relay (common) or SSR (as Nigel said).

For a light bulb I prefer a electromechanical relay, because it's not critical, you won't work with high speed switching and the electromechanical relay contacts can work with the light bulb currents.

But the choice is yours.
If you need some level of precision, use a SSR.
If you only need to "simulate" a common light switch, use a electromechanical relay.

 

[jemilsan]

you can also use Q4004L4 triac.

 

[nikhil arora]

I think relays will draw more current then a optically isolated triac or scr.

 

[mcs51mc]

Easy one

MOC3041 and triac is all you need !

Google for datasheets ...

 

[nikhil arora]

Please tell what is good to use to switch heavy loads more than 8A at 220V ac, heavy loads like Air-conditioner, Water pumps etc

A relay or a TRIAC which is cheap best and reliable option.

 

[zevon8]

You must remember the Engineering rule:

1) Cheap
2) Fast
3) Best

You can pick 2 choices from the list above, the remaining choice is what you will NOT get.

Solid state relay is the most reliable, but not the cheapest. A Triac, when properly designed into a circuit will be questionably cheaper, and relay is cheapest, but most likely to give problems later on.

 

[Analog]

how much do you have to spend?

 

[adnan_m_s]

electronic switch problem

Hi guys
I am facing a similar problem, I need to turn a switch on if triggered by a pulse coming out of an inverting op and to turn it off if it is not, most of the time the trigger pulse will be unavailable , I can't use a relay because it will get hot I need to do an electronic switch that could tolerate 12V 2A I thought of the triac but the problem it will keep swtiched on after pulse is off any help on this?, I need this circuit to switch power to a battery backup once main current is off so when the main current is on it will trigger an inverting op (powered by battery) to have the out put of the op in off state and when main current is cut off the op will give an output signal to switch on the cealed battery circuit 12V to act as the main power source understand what I mean? any good ideas anyone? any good diagrams or sites for that matter?

 

[manuvjose]

how can i make a RPM indicator using proximity sensor.?