Low voltage relay??????

Thread Starter


Joined Mar 27, 2010
HI, i m working on my semester project of password proected door lock using 4 bit comparator... when the two inputs or enterted combination and pre-set combination match, the comparator will send a high value of about 2V at its A=B port. i want to drive a relay using this low 2V voltage to trigger high voltage of about 12V. but i dont think so any relay exist that can work on 2V (Vmin = 5V is necessary to drive a relay).

So i need a model number of relay or Solid state relay that can trigger high voltage using low voltage of 1.8 or 2V....

i will be very very thankful if someone help me.....


Joined Mar 14, 2008
Just use a transistor to drive the relay. A general purpose NPN such as a 2N2222 should work. Be sure to add a transient suppression diode across the relay coil (cathode to plus side).

How much current is available from the 2V output?


Joined Dec 26, 2010
What technology of comparator are you using? 2V is a very low level. A schematic of your planned arrangement would help people to advise you.

Depending on how much current the comparator could supply, a bipolar transistor or an very low threshold FET might be suitable.

Typically SSRs require some milli-amps of drive current. Their actual input voltage may not be much more than you describe, but for consistent operation they are normally run from a voltage via a current limiting resistor.