Relay Help

Need help with a project? Trying to find a component? Post any general technical questions here.
Post Reply
Sidney
Posts: 4
Joined: Sun Feb 14, 2010 1:43 pm

Relay Help

Post by Sidney » Sun Feb 14, 2010 1:52 pm

Hello
I am trying to make a simple project that will convert a continuos charge of say 12volts into just one pulse.
What I am after is the equivalent to switching on a switch & leaving it on - but getting the same result if I had just pushed a bell push.
I think I am after a relay of sorts but not being too technical I am comming up with interval time relays , flip-flops but not really sure what I should be looking for.

Can anyone suggest a simple solution to this?

Thanks

Biffo
Posts: 72
Joined: Sun Mar 09, 2008 3:24 pm

Re: Relay Help

Post by Biffo » Sun Feb 14, 2010 10:42 pm

If your new to electronics then you will not go far wrong by using the ubiquitous 555 chip, very cheaps from somewhere like Maplins

probably hundreds of circuit ideas available for it as well ... like here..
http://www.kpsec.freeuk.com/555timer.htm

look up the monostable circuits that sound like what you mean?





.

Sidney
Posts: 4
Joined: Sun Feb 14, 2010 1:43 pm

Re: Relay Help

Post by Sidney » Mon Feb 15, 2010 4:00 am

Thanks that looks like being the answer.

I will read up on it & give it a try.

All the best

Sidney
Posts: 4
Joined: Sun Feb 14, 2010 1:43 pm

Re: Relay Help

Post by Sidney » Mon Feb 15, 2010 4:54 am

The monostable circuit looks ideal BUT would I be able to use it so it would trigger when the power supply is turned on?
What I would like to do is connect this to a 12v psu that it plugged into a remote controlled socket so when the socket is turned on remotely I just get one 12volt pulse.

Thanks

Biffo
Posts: 72
Joined: Sun Mar 09, 2008 3:24 pm

Re: Relay Help

Post by Biffo » Mon Feb 15, 2010 4:33 pm

scroll down this page to circuit 5

http://home.cogeco.ca/~rpaisley4/LM555.html

this should be what you are after? you can bridge the trigger (switch) and leave it because I think you want to work it from your power supply and it will still give just one pulse once the power is on,until it times out.

If I recall correctly the input voltage is 9v but your 12v will be ok.
you can adjust the timings/pulses etc just by the values of the resistor and capacitor , there is a calculator on the page for you to do that if you need to.



.

Sidney
Posts: 4
Joined: Sun Feb 14, 2010 1:43 pm

Re: Relay Help

Post by Sidney » Mon Feb 15, 2010 7:18 pm

This is really great. Thanks so much. Looking forward to giving it a try.

Post Reply