Muitimeter by GB Instruments model GMT-12A

Most DMMs will autorange and will also allow you to manually set the range. (Because it takes time to autorange, it's usually easier if you manually set the range when reading higher voltages.) Note that some ranges will require you to use a certain jack, usually the current ranges use separate jacks for the amps and milliamps scales.

Some common checks:

AC line voltage: Set to AC volts, place the plus and minus leads across the voltage you're checking.

DC voltage: Set to DC volts, place the plus and minus leads across the voltage you're checking.

Continuity: Choose either the ohms or diode check scales. Touch the positive and negative leads together and verify a reading of (almost) zero. Make sure there's no power on the circuit your testing, then touch a lead to one end and the other lead to the other end. Verify zero reading. Then touch one lead to ground to verify circuit is not grounded. Tip: If your leads won't reach both ends of a wire, just check for a short to ground first on one end, then have a helper ground the other end of the wire; if the resistance goes to zero the wire is good.

Diode check: Diode must usually be out of the circuit. Switch to diode range. Hold plus and minus leads to the diode leads, then reverse. You should have continuity in one direction only.

Current (Amps): First make sure that your meter can handle the current you want to test. Most DMMs can handle 20 amps max. Pick the appropriate scale (e.g. for an AC motor, pick AC amps). Put the leads in the appropriate jacks (usually "-" and "20 amps"), then connect the meter in SERIES with the load you're testing and apply power. Note that if you put too much current through the meter, you'll blow a ten dollar fuse inside the meter.

If there's a specific test you need to make, post it and I'll suggest how to do it.

Will probably have an AC scale, which you won't use on or around a tractor or vehical, since is DC but will come in handy around the house for measuring AC. Your DC scales, like your AC scales may come in multipliers (10 or below, 300 or below, 600 or below, etc.), so going to need to find your scale (the first one greater than your value of 6 or 12VDC) and go across your terminals with the probes. DC's polarized, AC's not. So if put your probes across the battery terminals for instance, and the meter tries to go negative, reverse the probes and get a proper reading. There will undoubtedly be a scale for measuring resistance (measured in ohms) that will probably be marked Rx1, Rx10, Rx100, etc - great for finding shorts, reading components, etc. To test it, turn the dial to Rx? and touch the probes together, then adjust for zero so is referenced properly for that function when you begin. Don't read across a voltage in any "R" position, or can/will pop the internal fuse, but can read a leg that's hot without blowing the fuse. What I mean, don't read across the battery terminals in the "R" position, but can read from one battery terminal to the other end of the cable connected to that terminal while the cable's hot. When you look at your meter, will have different scales marked in different colors, marked to coincide with the different positions of the dial of the meter. The manual will do a better job than I can or did, but those are the basics.

Always shut the meter off when you are done, there's an internal battery used for the Ohm scale (resistance) and will go dead powering the meter, much like leaving a transister radio turned on. Be careful when probing around so you don't hit the wrong thing, short the meter, short a vehical component, melt the probe leads, etc.

Excellent tool you got yourself there. Learn how to use it, you'll love it. One of the most basic and important when dealing with electricity.

Good luck, enjoy it, use it in good health. Don't get discouraged. If I can do it, you can do it better with practice. Next tool? Pick yourself up an O-scope. Won't do resistance readings, but will do everything else, and a world more.

Mark

Generally there will be three terminals at the bottom of the meter. One will be something like "COM" another will have something like "A" or "10 A" and the third will have many symbols such as V, ohms, etc.

To test for voltage you will want the black lead of the meter connected to "COM" and the red lead connected to the terminal with a V.

For DC voltage, as from a generator, you will want to turn the knob to something that either says voltage DC or shows 3 little dashed lines and a solid line. With the tractor running you can then connect the leads across the generator output terminals.

For AC voltage, as from a alternator, you will want the knob at either voltage AC or a symbol like ~V. With the tractor running connect leads across generator output terminals.

In a 6 volt system the generator should put out around 8 volts when running. For a 12 volt system the voltage should read around 14 volts for a functioning alt/gen.

Hope that helps