I am designing a power control panel for the room of many applicants. In the panel there are several micro switches available for the user to turn the appliances ON/OFF. At the end of the micro-switch there I place relay for controlling load of 220V (AC). I am powering the circuit by 12 volts.
I want to freeze the state of relays either ON or OFF such that; when user presses the micro-switch once, the relay should turn ON until the user presses the switch again.
Which component should I use to maintain the state of relay?
Best Answer
You could use a latching relay for this, they are designed to maintain their state (without constant power applied) once switched. You just need a brief pulse (e.g your 12V for a 12V rated relay) to toggle.
Here is an example part, rated for 250V/3A.
You don't mention what current it needs to handle, but if you search for "12V latching relay" on any of the large suppliers you will get plenty of options from which you can select a suitably rated part.
Bear in mind these are a bit of a pain to drive, as you need to reverse the polarity of the pulse to switch on/off (or have another coil connection for the 2 coil version, which if you only want to use one button would be a problem)
If the extra power consumption isn't too much of an issue I think I would probably go for Abdullah's suggestion of a T flip flop driving a standard relay. They are also a lot cheaper.