I need ideas for a cheap power supply with a battery backup I need a 5amp 12v pulse for 0,5 seconds to drive a reversible dc motor. The pulse is needed to power an actuator that opens a lock.

 

I need a circuit diagram for a delay off relay 12v and 0,5 seconds on then off

 

Please supply a LOT more information.

What is the relay coil resistance?

What is the power source for the circuit?

What do you mean by "delay off"? Do you want the relay contacts to close for 0.5 s when power is applies, then open indefinitely until power is cycled? Or something else?

Is this for an industrial environment? Outdoors? Under water?

ak

 

What is the shortest time period between output pulses?

What is the power source for the circuit? Voltage? Available current?

How accurate does the 12 V value have to be? +/-1 V? +/-20%? etc.

Are there environment or size or cost constraints?

ak

 

Off delay usually implies ON when power applied, and delayed drop out at power OFF

 

Any size constraints on the battery?
Otherwise a small, sealed, lead-acid, absorbed-glass-mat (AGM) battery (such as this) can deliver a high pulse current, are relatively cheap, and easy to trickle charge from a small 15Vdc (wall-wort) supply.

 

And what is the tolerance on the 0.5s delay time?

0,4 to 0,5