wiring question

Measuring voltage is easy. Just turn the dial to a voltage range higher than you will be working with - usually the 20 volt DC range for RV work. The meter should handle reverse polarity by showing a minus sign on the voltage so no worries about which lead you touch to positive or ground.

Measuring current is more complicated. Best to have a knowledgeable person watch you do your first measurements. Choose a high current range to begin with - too low and the overcurrent may destroy that range. If you connect the meter as you would a voltmeter, you will certainly blow the current range on a low cost meter because current meters offer very low resistance to the current and very high current will flow through until something burns out. The thing is, in order to measure current the current has to flow through the meter. So you must unhook or cut the wire and use the leads to make the current flow through the load AND meter.

My low cost multimeters came with poorly made probes; the lead always breaks off the probe handle. I solder them back together with some difficulty. I finally realized that it is much easier to solder an alligator clip on instead of a probe - and the clip is usually more convenient in use.

Your hardware store will have a multimeter that includes a voltmeter. $25 or so will get you more than enough tool for this purpose.

If budget is tight, you can also get a tool that looks like a screwdriver with a pointed tip, and a wire with an alligator clamp on the end coming from the top of the handle. Clip the wire to a ground on the RV and touch the wires until you find the hot (a bulb in the handle will light up). But multimeters have so many uses that, if you can possibly afford one, get it.

wolfe10 wrote:

2oldman wrote:
Voltmeter.

X2

X3.
They're cheap on eBay and if you don't have one now, you'll sure need one in the future!

Cheers,
Scott

2oldman wrote:
Voltmeter.

X2

Use splices like this and you will not have to cut the wires. Attach a pigtail to each wire and use your voltmeter to determine polarity. Then attach your camera wires to the correct pigtails.

Voltmeter.