pulse inverter?

This was posted in a topic a while back.  It is for converting a negative pulse keyless signal to a positive pulse to use for positive triggered door locks.

Quote:

You could use two PNP transistors and a few resistors to accomplish this.  It's pretty basic electronics,   your just using the transistor as a switch.   The negative lock or unlock signal gets fed to the base of the transistor via a resistor (1K - 5K),  The Emiter goes to 12V and the Collector would now be your Output.   The Base can also have a 10K pullup resitor to 12V.   Probably a buck or two in parts.

Does anybody know exactly how to make this?  What is a pullup resistor?  How do you know what size resistor to use for the (1K-5K) and what transistor (part #) would I use for this?

Thanks.

A pullup resistor is simply a resistor used to provide a bias for a transistor (or any other electronic part).  Basically, it provides voltage to the circuit for use as a reference.  When you apply a ground to that reference point the pullup resistor will turn in to a load resistor and you'll be left with 0vdc at your reference point. They are very useful in digital electronics to make sure you are above your switching threshold, or in this case, to make sure your transistor is turning on.

It would be easier to just use a DEI mini relay, or any other smaller, 10A relay.

Here is a quick drawing of what the post above is talking about.  I would definately test this before putting it in a car, as I just drew this up quickly.

For the record, I have used something like this in one car, and it was for a brake shutdown on a turbo timer.  A relay would have worked, but it clicked everytime he pushed the brake pedal in, so we went this route.

I found the pulse inverter I was looking for at a local alarm shop.  That is exactly what it looks like inside.  4 resistors and 2 transistors.  Mine came with a connector that plugs right into my remote start module.  Only $8.  Lots easier than building one, but not as fun.  Thanks for the help, though.