Hi all , i am Ahmed from egypt...
First of all , GREAT work , really great forum.
I have a small project , and i need help from every one who can help me.....
What i need is a switch circuit drives a 12v relay at exactly 3 volts or more.
i mean a small simple circuit that closes the 12v relay when the input signal voltage of the circuit reaches 3 volt and opens the relay again if the signal runs below the 3v , and that circuit operates at 12v.
PLEASE this is my first request in this forum , so Plz help meeeee !!
any circuits , any links , any ideas anything
thanx , i had seen the circuit , but i can't understand anything .
The cicuit i need is not to switch between 3v and 12v , it runs on 12v , and the input signal is 3v max. so when the input reaches 3v or more the circuit output closes the relay.
Thank you very much
Hi Ahmed,
In your other post about a tachometer circuit driving a relay https://www.electro-tech-online.com/threads/dc-motor-speed-controller.14649/#post-78754
I said that your tachometer IC already has a comparator and a relay driver transistor.
I have re-arranged the "Speed Switch" circuit in the datasheet for the LM2907-2917 from the 8-pin IC that is shown to the 14-pin IC that you have: