I'm installing 5 autometer gauges in my el camino. I want to use an adjustable resister to vary the internal gauge lights. Should the lights be wired in series or parallel? I don't want to use/overload the stock light switch. Thanx.
Thank you John, i appreciate the info. I did a search, but that didn't show. I'm gonna tie the wiper connection to the 12V input connection, then take output from the third terminal. Does that sound about right?
If you get a potentiometer with an off position you will be able to turn them off during the day. There's 2 basic kinds of pots: linear taper and audio taper. Has to do with resistance increase through the pot travel. Look for something that's a linear taper pot. It will dim more evenly. Don't forget about the pot's current rating.
Where are you getting the potentiometer? The little 2W dial jobs you can get at electronics places probably won't cut it.
You have to find a very low resistance, high power potentiometer. I don't know what the stock switch dimmer resistance is but I'd bet it's no more than about 5 ohms. It also looks to be about 10 or 20 watts.
You have to know the resistance of all the bulbs when on. The best way would be to measure the current draw and the supplied voltage to calculate the resistance. Then, find a pot about 5x the resistance. The power rating has to be calculated for a pot resistance = to the bulb resistance.
If you've installed these autometer guages then you've probably removed some of the origional dash equipment and therefore, the origional dash bulbs. If this is the case, I really don't see a problem with wiring the new guage bulbs in their place.
You are right. I realized (once I started syphering my ohms law) that the 3 watt (25ohm) pot from Radio Shack was not gonna hack it. The bulbs in the 5 gauges are about 7-7.5 ohms. The last real electronics supply store in this city has closed and www.partsexpress.com doesn't carry anything suitable. I'll go with an on-off switch for now. Thanx.
A series connection is when you connect the parts so the same current flows through all of the devices. For example, take a bunch of lights with 2 wires coming out of them. You connect one wire of the first light to the +ve and the other wire to one wire of the next light. Then the other wire of that light to the next light. And so on. Last wire goes to the -ve.
A parallel connection is when you connect all of the parts with one terminal to the +ve and one to the negative.
How the wires are pysically routed to achieve the connection has no influence on describing it as a series or parallel connection.
O = bulb
negative terminal is last - at right
| | | |
| | | |
this - is the negative terminal.
I'd do better pictures but HTML doesn't seem to allow for double spaces in the document. Hopefully you get the idea.
A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!