Technical HOW TO USE A MULTI METER/VOLT METER

I know there are a few people on here who can tell us all the basics and some great tips on how to use a meter to test and troubleshoot wiring and components. I have tried to help solve electrical problems and seem to have to start people off with the basics of testing with a multi meter. Help us learn how to use these instruments.

 

Chances of the meter being readable by the time you get your head and both probes in position - doubtful.
Wish they would make a meter with a digital readout right at the probe.

 

I have a few multi meters and will often refer to them as a volt meter, not to be confused with an amp gauge or volt meter in dash. These instruments can tell you if there is voltage in a wire or system. Make sure that the battery is good in the meter or you will get different readings all of a sudden. I recommend a digital meter with an audio continuity setting. It looks like a little bell or something on the dial and gives a continuous beeeeep when you touch the two probes together or at both ends of a circuit or wire you are testing. You can get one at Sears for $25 up.
Most of the time on topic testing will be VDC (volts DC) and the switch will be on the 20 volt range.

 

Haven't seen one of those yet.
I have a bunch of jumper wires of various lengths w/alligator clips that I connect to whatever I want to check and then to the probe. Sometimes it requires a covered alligator clip for insulation, so if you make some, you might choose covered clips. I also made up some with a spade connector to speed up the process of checking those wires.
Those long sewing needles with the plastic tips can be used to stick in a wire or connector, so that circuits can be tested while running. Just hook an alligator clip to the pin then to the probe.

 

Gee I wonder who supposed to read that.lol.Bruce.

 

I think the most common uses for a mulitmeter on a car are - 1.) Checking for 12v, 2.) checking for continuity, and 3.) checking for amp draw... and for #1, a test light is easier if you are looking for a yes/no answer, while the meter can tell you if that 'Yes' is 12v or something less/more.

 

When using a multi meter to test automotive circuits and voltage, test battery voltage first so that you know what number you are looking for and if there is any loss in a circuit.
Basics: Red lead goes in + hole in meter and reads battery positive
Black lead or probe in ground- hole and reads battery negative
If you get a negative reading on screen, reverse probes where testing.

 

I have been using multimeters all my life but for just checking if there is voltage present I prefer a test light. If the amount of voltage is a concern such as that feeding an ignition system then you need a meter. I prefer the old analog type(maybe because I'm old) but a good one is hard to find these days. In electronic circuits we found that the digital ones will sometimes show a small voltage when none is there. Use an alligator clip to connect the common lead and forget that one, then you only have one lead to move around.

 

Bruce, I am hoping we can all learn about this. My knowledge of this tool is suprisingly limited and there are some experienced people on here. I hope we continue to hear from them.
I'll try to get some pics going soon.

 

Let's get real basic in the beginning and build on that. I know sometimes the dial on an analog meter may be confusing. How about helping readers understand the dial/setting relationship?
Good point on test lights, let's include them in this discussion. I always test mine first on a known source of power to make sure the bulb is working and the ground is connected, or wish I had.

 

So far everyone has confirmed why I'll never understand electricity, NOBODY uses the same terms, gauges, or volts, amps gigawats or whatever measuring unit you care to use. Block sanding bodywork and having a great time. They don't have to run to be enjoyed. Bob

 

Maybe we can get on the same page about what to call things and all learn.

 

great idea for a thread, thanx for starting it and to the contributors. when you`re trying to learn something new it`s always best to start out with the basics.
tom

 

Hi Rob
I'm sitting here with a BIG grin right now...

 

Thanks.

So, the horse hoof is Ohms and is read on the light blue scale.
Is Ohms the resistance of flow of current?
DCvolts - Car stuff
ACvolts - House shop wiring
All read in the center black scales, based upon where you have the dial set - 10, 50, 250 -
mA - milliamps
db - lower red. What is that? The noise level when we hit our head under the dash or something?

 

So here's the deal: this meter has 3 dc voltage scales, 10v dc, 50vdc, 250vdc, those are the three black scales, and 3 corresponding positions for the rotary knob. Use the scale that matches the knob setting. To measure 12 volts, set the rotary knob to 50 vdc and read the scale that goes from ov to 50v. This meter is set on the 50v scale and is reading 1.5 volts. A 20 volt dc setting would be better for measuring 12 volts but this meter does not have one.

 

just curious but why don't you measure your 1.5 volts on the 10 volt scale?

 

I couldn't find a picture on the interweb showing a meter measuring 12 volts. I guess this guy was hoping to measure 12v so he's on the 50v scale, but all he reads is 1.5. Maybe he found his problem.

 

In regard to Blowby post # 2 here is a pen type digital multimeter http://www.ebay.com/itm/Pen-Type-Di...oltage-current-LOGIC-Test-probe-/111472470385

There are many other manufactures

 

Ohms is resistance, not continuity. When checking ohms there is no power running through the wires you are checking high resistance in the line. To check for Ohms, put one lead (red) to one end of the wire, put the other lead (black) to the other end, should show less than .5 of ohms per resistance per foot. Current is checked in amperage or "A"or Milliamps or "MA", shows continuity under load in the line. Everything automotive for the most part is checked on the VDC scale of 50V, unless you get into computer controlled vehicles, a lot of devices are run off of MA, or low 5 volt memory communication reference. That'll lead down the road of OT..

 

Power probe 3 is probably the best checking tool out there besides a Fluke 77.

 

Nope either way will work. Yes, turn the dial to the Ohms scale. If it shows a rather large reading, there's excessive resistance in the line. It's good for checking all sorts of things, switches, gauges, etc. BTW my wife says that all the time..

 

Sweet! I really need to branch out from HF...

 

Sorry prime, I deleted the post that asked if it mattered what color probe went where, becaused I noticed you had answered it. And the, "That's what she said" comment.

 

My favorite multimeter that I use daily is the fluke 88. It has most every function I've ever needed. It even has dwell

 

Here's a how-to I did from another site....

http://www.xs11.com/forum/showthread.php?t=35338

http://www.xs11.com/forum/showthread.php?t=35339

Note the second one is targeted at that particular bike, but the methods and quality of connections would be the same for any vehicle system.

 

We just came up with a new marketing slogan for HF tools: Better than nothing!

 

I second that. You can diagnose most any automotive electrical problem with a power probe. I use mine all the time. It's great because you have switched power right at the tester to check bulbs, relays, and such.

http://www.powerprobe.com/

 

Steve, I was hoping you would see this. Did several searches and got nothing. I really want to learn how to use a meter properly, so will dig into these threads. Hope you hang with this thread and share your input. Thanks in advance.

 

Tell us all you can about these, rough cost, and how to use them.