constant to momentary

No, the relay does not supply ground on terminal 30 (output wire).  Are you using a polarized capacitor? If so, what size?

the12volt • Support the12volt.com

Please double check all of  your connections.

30 is the output wire that provides a momentary 12V+ immediately after terminal 86 is connected to 12V+ through a switch (Accessory, Ignition, etc.). Terminal 87 goes to a constant 12V+ source (battery). Terminal 85 is connected to a polarized capacitor and resistor wired in parallel that are each connected to ground as shown in my diagram. Terminal 87a is not used. Pay close attention to the diode across the coil. The cathode side (with stripe) is toward 86. The anode side is toward 85. If necessary, bench check it before installing it in the vehicle. I've used this configuration many times and have never had an issue with it.

the12volt • Support the12volt.com

I'd like to go from a constant 12 volt input and as it loses 12 volts it pulses 12 volts to the other side . Is it possiblle?

Are you needing a 12volt  pulse when the relay de-energizes?   If so, it will take 2 relays, but I am sure we can figure it out for you.

It would help if we knew your exact application.

Hi,

New forum member looking for some help.

My application requires a 12 volt pulse of 1/2 seconds 50mA. The tricky part is that I need this pulse when the contstant 12v is applied and also when it is removed.

Any help appreciated

Luca

I have a diagram that I think will work for you.  I have not built and tested it yet.  It may take a 2200 mic capacitor.  You will have to build it and test it.  My thinking is that when the left relay is turned on, it will energize the right relay until the capacitor charges, then the right relay will disengage, that will be the piulse when the wire goes positive.  When the wire goes dead, the left relay will now place ground on terminal 86 of the right relay.  The cap wil be charged, thus powering the right relay briefly.  This will be your pulse when the wire goes dead.

In case you missed it earlier, I have not built and tested the above Idea.  You will have to test it before attempting to install it in a vehicle.

You can ditch the resistor, it will not be needed.  Test it and let me know if it works.  Changing the cap size will change the llength of the pulse.

Thanks I am an idiot,

I will get the parts today and substitute the 1000uF cap for a 2200uF cap and also remove the resistor.

Just to let you know the application is for home theater use. I have a Classe CA-150 that requires a 12 pulse to turn it on and a 12 volt pulse to turn it off remotely. Most components only supply 12v constant nowadays, so this is why I am looking for a solution.

Thanks for your help

Luca