I am trying to figure out how to get a .5v signal, to power a 12v device. I originally figured just use a relay, but from what I can tell - the relay will not activate from just 0.5volts

any ideas?
mainly something simple I can get/make from radioshack (tonight)?

thanks in advance

 

u'd need some sort of POWERED amplification, why are you trying this?

 

This project may be a pain.

 

wow.... i dunno about .5V

 

wat kinda application requires a .5V power signal?

 

You could use a transistor switching circuit. Here check out this link to get some ideas http://deztex.virtualave.net/sc1/sc1trans3.html . There is a relay based switching circuit at the end of the page that I think would work great for your project. The only thing I would suggest to do differently is to use a germanium based transistor as opposed to a silicon one. The reason being is that Si based transistors drop about .6~.7 Vdc across there base, which in this case would null out your .5 Volt signal. A germanium one if I recall correctly only drops about .3 Vdc at there base.

If that doesnt work you could always build a 741 op amp voltage amplifier to boost your .5 V signal to a couple of volts and then have that feed into the Si transistor relay switching circuit. I wouldnt directly power the relay with the 741's output because it might draw to much current thru the 741 chip and kill it over time. They go into some explantion as to how op amp circuits work on that website.

All these parts can be purchased at Radio Shack for pretty cheap and can be put together by someone with decent electronics experience in about an hour or two. (by my estimate)

Hope this helps.

 

Yea ummm what he said.

 

Yeah, I thik you're on the right track. A relay is used for exactly that. And if you're doing what I think you're doing (trying to get a window switch to activate a nitrous solenoid) MSD makes the relay for that. I need it too, but right now I just have the window switch grounded out (bypassed). Now if I could just remember that relay number....

 

A standard automotive relay is used to take a low amp 12 volt signal and use it to switch a higher amp 12 volt source. If you look at the specs on a relay, it says it requires something like 10 volts to activate, and then it will deactivate when it falls under 4 volts. He is coming from a .5 volt signal. Nowhere near enough to trip any kind of relay.

The window switch from MSD is RPM activated. That doesn't sound like what he is trying to do, cuz the tach wire pulses, doesn't it? What can you do with a pulse? Nothing, unless you have a circuit, like in the MSD window switch.

Maybe you should tell us more about what you are trying to do.

But whatever it is you are trying to do, I think you will have to listen to 98SEBlackMax and start getting fancy. Hope you have some kind of electrical experience!

 

Look into the PAC Trigger Modules TR-4. I am not sure if it will sense voltage all the way down to .5V but they do claim to sense down to .8 you might be lucky.