I'm playing around with an electric car antenna to see how I might be able to use it within an arts project & it took me a little while to realise how to wire it up outside of a car. As always its simple when you know how, so in case anyone else needs a prod in the right direction here's what you do:
I've got a mains powered 12v DC power supply with three connectors: +12v, -0v and Ground. The antenna has three wires: Red, Blue & Black.
- Connect the red wire to the +12v terminal so its always on, this provides power for the antenna to retract.
- Connect the black wire to the -0v (Negative) terminal. (the instruction said ground which threw me, see notes below)
- The blue wire acts as a switch (powers the other direction) to expand the antenna. So whenever you attach it to 12v it will expand.
The thing that briefly threw me were instructions stating that the black lead should be attached to ground. After a quick google to get clarification: "For many electronic circuits, ground is the 0V (zero volts) of the power supply, but for mains electricity and some radio circuits it really means the earth". So as a cars electrical system is insulated from the earth by rubber tyres, any reference to ground in that instance would actually be 0v (-), the negative terminal, hence my slight confusion.