Hi,
I am trying to set-up a circuit which basically involves a push button switch and a relay.

What I would like to know is, is there any method of having a 3-5 second delay on the relays switching by using resistors and capacitors, or would a timed latching circuit be needed?

So the circuit I am trying to figure out is:
When I push the manual button switch, It would take the relay 3-5sec to switch "on", once my finger releases the push switch the relay returns to its original "off" state immediately, without any delay turning off.

This circuit sounds very simple but I just cant seem to put it into practice.

Thanks for your help!

Regards NM

 

There are timer relays out there (CUH42-30010), but there not necessarliy cheap.

 

Yes they are expensive,
But there must be some alternative method that can be made up with an ordinary relay?

 

i think this circuit may suit your need.

 

Perfect,
Many Thanks rwmoekoe!!

 

my pleasure

 

rwmoekoe beat me to it

But as long as I worked it up, might as well post it...

Attached is a variation; S1 should be a pushbutton momentary. It was easier to model using a SPST

 

It's possible to do with one resistor, one electrolytic capacitor, and an SPDT pushbutton. Component values depend largely on the relay's coil resistance, and the pull-in voltage. No claim for compactness here, as a 300Ω relay would require about a 10,000µF capacitor for about 3 seconds. The resistor and capacitor determine the time to discharge the cap before the next delay.

Ken

I made a mistake. My circuit does just the opposite, and acts like a monostable. Turns on immediately and turns off after a delay.

 

Thanks for taking time to help me out guys!
Much appreciated!
NM

 

I have to design a relay digital to protect generator. It has 3 function: stator false ground, rotor false ground, overcurrent stator. Generator is synchro 3 phase.
Please help me (