negative to positive inverter

Sorry kids I'm with Uncle Gary here Mr. Ween, I get the impression you do a lot of BlueTooth kits. For adaptors for exotica from 2000 on which kept changing their plugs and layout, e.g. BMW and Mercedes, look at Kram in Denmark, they actually manufacture a lot of head unit plugs as OEM for European manufacturers.

no, just a little bored today, caught me in a good mood.

Mike M2 wrote: I can't see the point. A DEI 451M is designed to do this exact same thing...

I generally think the opposite - why use a relay when a simple transistor will do.... Small, quiet, reliable. No clicking, no BIG caps and resistor needed for delays.... All you need is a typical "Open Collector" output. A +ve voltage via a resistor to the Base of an NPN transistor. The Emitter is connected to GND (0V). The Collector is its output - it connects to ground when the Base voltage exceeds ~0.7V. (There's a bit more, but KIS for now.)

KarTuneMan wrote: KPierson wrote: I would run a 470 ohm resistor in to the base of a PNP transistor (like a 2n3906). The other end of the 470 ohm resistor would be your (-) input. I would connect the emitter to 12vdc I would connect the collector to a 22 ohm resistor. The other end of the 22 ohm resistor is your (+) output. I would connect a diode between the (+) output and ground. The 470 ohm resistor provides your base current. The 22 ohm resistor protects the output from excessive current that can damage the transistor. The diode protects the transistor from reverse voltage spikes caused by the collapsing of magnetic fields most commonly found in relays. contract installer..... what is your time worth?

  My time is worth about $100 per hour. I am sure time wise it would not be cost effective. But It would be someting to do in the off season and possibly I might learn some thing too. I perfer to make my own transponder bypasses vrs useing a transponder box. So maby knowing how to make my own inverter with some cheap radio shack parts could be usefull in a pinch. If maybe I run out of relays or inverters. I would think it would take just as long to wire up2 relays as it would to solder up a inverter.Solartech Window Tinting and Electronics,contract installer

And here endeth this post. Everyone is right; no-one is wrong, keep to your views, try the other's philosophy if it works.