What is the best Multimeter brand? I hear Fluke is pretty good. They have them in store around my area. Is it easy to understand how they work and are they worth buying? I need one that tests resistance as well as volts, amps, watts, etc. Is there one that does all this?? Thanks.
Hi. I don't think there is one "best" meter, but which one is a best fit for what you want to use it for. Yes, my experiences in the electronics world that required very precise measurement were served well by the Fluke meters we used. That said, cost was a secondary consideration at that time.
In the hobby world, how precise do you need to be? If +/-10% accuracy is sufficient, a super-cheapie is all you need, and spending a bundle isn't worth it. If you need better accuracy, then the price will rise. Ongoing real accuracy also requires scheduled trips to the recalibration lab; and that's not free. I just got a small clip-on ammeter for peanuts that I used to service my electric furnace, where my regular serviceman has a meter he paid many times more for. I don't need to know exactly, just that a reasonable current was flowing. He can likely drop his meter, mine wouldn't survive.
Usually, if you need wattage measurements you will need a separate meter for that. The usual multi does ohms, volts (AC & DC), and small amps measurement. Doing amps requires that you disconnect the circuit and route it thru the meter: a couple of amps max.
You don't say what you are measuring, but be aware that all voltages can be dangerous, even the lower ones that leave a circuit charged and awaiting an errant finger or tool. Even the pros get burns, and flash damage in the eyes if their guard is let down for a moment. Wear those safety glasses!
Have a safe day, George.
I don't know what the best is, but i have had my Fluke Multimeter for about 15 - 20 years and it still works perfect. I think I heard somewhere that Simpson's were the best.
Bill
Ive had my Simpson analog multi-meter for over thirty years and my Fluke digital for almost as long. They are both quality items that were made to last a lifetime. There is something to the addage: you get what you pay for.
For hobby use, any low cost meter from Radio Shack will do.
As for me, before retirement, my employer , one of the largest in the U.S., supplied me with Fluke or Beckman meters and scopes. Great quality "TOOLS".
Don U. TCA 73-5735
I used a 20 year old cheapo Radio Shack analog meter. For as often as I use one it serves it's purpose.
Paul
I have a digital Craftsman meter $25. Works great! I use it for the trains and to test resistance in audio cables.
Kurt
Okay, I bought a $25 one at sears. Not sure on how to use it, but, I have a pretty good idea from what the directions say. To test volts on AC current, you out the black lead on the ground or outside rail and the red lead on the middle rail or power rail. I tried this with my transformer at 10 Volts on dial, and the Multimeter read about 5 to 6 Volts. What does this mean? My output is not that good? I tested all the way around that loop of track and says the same. How do you test resistance?? I had the transformer at 0 volts and tested the same way on the track and it read 0 resistance. Should I have volts on the transformer at 10 or so volts or keep it at zero? All I really wanted to do what test volts that the transformers are putting to the rails and the resistance, so I know to maybe use bigger wires. Thanks.
Okay, I read the manual a little more deeper. Says that when testing for resistance I should put the meter at 2000K Ohms. And turn down all power. Meaning, have 0 volts on transformer. What is a good reading range for resistance for like loop of track, about 40 feet of track in a loop?? I am pretty sure I know how to test volts. Its pretty straight forward. But, ohms, I am not sure about what ranges are good for what wires and tracks. Is there a web page or something that will explain all of this?? Thanks.
Unless you have a true-RMS meter, which is unlikely at $25, your meter actually measures average rectified voltage and scales the result to RMS volts on the assumption that the waveform is sinusoidal. This is correct for postwar transformers, but gives answers that are generally too low for modern "transformers" like the CW80. In your case, it is more likely that the markings on the transformer dial are just not that accurate. Try measuring the full output voltage, which should be about 25 volts for the Z and 21 for the ZW.
Do not try to read the resistance of anything that is turned on. You will not get any meaningful measurement and will most likely blow the fuse in the meter. You will not be able to make any useful measurement of your wiring resistance with your meter--it is just too low to measure even if it is too high for your trains. Instead measure the AC voltage drop along the wire with the train running by putting one probe at each end of the wire (at the transformer and at the track). Do this for both wires of the circuit. The voltage drop should be well under a volt.
Bob Nelson
Did you buy the Craftsman model 82140 by any chance?
Yes, that is correct. I have that model.
I am still not sure what you mean on how to test resistance. I understand how to test for AC volts. No problems with that. Now, you said that testing resistance I would want the Z transformer and all its dials set at 0 volts or all the way down. Now, how exactly do I test the resistance of my long stretches of track to make sure that I might have to add another lockon, where the power get less. And for long stretches of wiring, where to add thicker wire. Thanks.
I used a Fluke at work and bought a cheap Radio Shack Multimeter for home use. The Fluke is much nicer, but much more expensive. The biggest complaint I have with my Radio Shack multimeter is the long time the meter takes to settle on a value. For example, the meter usually goes to zero ohms when I read a resistance value and then slowly increases to the actual value.
Earl
Okay, I tested 3 out of 4 of my lines. All tested about 23.4 Volts at various parts of the layout. Nothing went higher than 24.2 Volts on my Z's. Did not test the ZW or KW yet. But, I will soon as I get my (4) 022 switches wired up tomorrow and then I can test that 4th line. My main line tested very good, as did my gang car and elevated lines. But, I will check that inner loop, the one with like 12 switches on it. Should I set the resistance Ohms at 200k? And what is a good reading for that level? Now I should have the transformer plugged in and on, but not volts applied to the track or wires at all. Then test for resistance. Correct?? Thanks.
No. Unplug the transformers before trying to measure resistance.
You will get a much better measurement of the resistance of your wires simply by measuring their length and multiplying by their resistance per unit length than you can with the ohmmeter, which will measure not only the resistance of the wire or track but also the resistance of its own leads and the contact resistances at the ends of the leads. The resistance you want to measure is less than an ohm. The lowest scale on the meter is the 200-ohm scale. You really need a much lower scale. The only reason for knowing the resistance anyway is to calculate the voltage drop. But you can measure that directly, without any error due to the meter's leads. If you want to include the effect of the track, just measure the voltage between the point on the rail that concerns you and the transformer terminal. If those points are farther apart than the meter's leads will reach, use a piece of wire of any gauge to extend the leads. But do this with the train's locomotive running past the point of interest, so that a voltage drop will develop in the wire and the track. A measurement with no train running will be zero.
Im not sure why you seem so bent on using the resistance part of the meter? Basically, you only need to check resistance if you have a short, or suspect a bad track joint and you can check the resistance across the joints. Resistance should be near zero for best connections. Its good for checking open connection on motors, diodes, resistors, etc. NEVER check resistance under power! Depending on the meter, you may permanently damage it.
Roger
Okay, Lets say my resistance is 10 ohm/kft. To make it simple. And my lengh of wire is 10ft. Then my resistance is 100 ohms. Is this right?? And is 100 ohms too high for 10 ft of wire?? I just choose 20 AWG copper wire to make it simple. I gotta look up 14 AWG to see what its resistance is. Okay its 2.5 ohm/kft. Then 10ft of wire. It would be 25 ohms. Is this right and what does 100 ohms and 25 ohms mean? thanks.
Opps that was for per 1000ft of copper wire. It is .0119 per foot in ohms for copper wire resistance. So 10ft of 20AWG wire would be 0.119 ohms. And 10ft of 14AWG copper wire would be 0.0297 ohms. I can now see the difference between the two sizes of wire. Closer to zero is better i take it.
You've got the resistance calculation right now. Notice that these are rather small numbers, which is what makes them hard to measure with a simple ohmmeter like you've got.
The unit of resistance is the ohm. One ohm is the same thing as one volt per ampere. So you can take the current in amperes that your train draws from the transformer, multiply it by the combined wire and track resistance in ohms (volts per ampere), and get the voltage drop along the wire and track. If your train draws 5 amperes and your wire resistance is .1 ohm, you will have a .5-volt difference between your transformer terminal and the other end of the wire. (This relationship, E = I*R, or voltage equals current times resistance, is known as Ohm's law.)
What I have been saying is that, since circuit resistance, especially the part in the track, is so hard to measure accurately and, since you don't actually know exactly how much current the train draws anyway, it is better to measure the voltage drop directly by connecting your voltmeter between the transformer terminal and the rail. As the train passes the measurement point, you can read the voltage drop. Note that measuring without the train should always give you a measurement of zero because, when the current I is zero E = I*R = 0*R = 0.
There is resistance in both of the two sides of the circuit, feeding the center rail and feeding the outside rails, so you should make two measurements. The total voltage drop that affects the train is the sum of the two. There is also a voltage drop due to the internal resistance of the transformer (which is not zero). However, there is nothing you can do about that. All you can do is to keep the wiring and track resistance from adding significantly to it. In any case, the transformer resistance is the same no matter where the train is on the track; so it doesn't affect the train's speed in the way that track and feeder resistances make the speed vary as the train moves around the layout.
Bob,
You have given a lot of very good advice. I would add one thing: When measuring the voltage drop at any point in the layout, just measure between the center rail and one of the outside rails with the train nearby and powered. Then measure the voltage at the transformer. The difference is the combined drop in the center rail power and outer rail power. Now if you want to determine whether the drop is in the outside rail or the center rail, you will need to make each reading individually.
58 years ago when I got my first train, I didn't have a meter, and neither did anyone I knew. They were quite expensive in those days. I used to watch the train run, and if it slowed down somewhere, I would either add another power feed or check for a loose track connection. I still use this method. I also make sure the track connections are tight when I put a layout together, and use crimping pliers (the pliers you would use to crimp lugs onto the end of a wire.) to shape the open end of the track. The crimping pliers also work well to crimp the pins so they don't pull out easily.
You're right, you can just subtract the measurement at the train from the measurement at the transformer.
I suggested the other method because the measurement at the transformer would have to be taken with the train at the same place on the track as it was when the track measurement was taken. The reason for this is that there will be some drop in the transformer itself. You wouldn't want to include that in the measurement, since it will be there no matter how many or how heavy feeders you install. The two measurements would require running the train past twice with the meter connection shifted between measurements and without disturbing the transformer setting.
You could also run a temporary pair of (small gauge) wires from the track location to the transformer, with a DPDT switch to connect the meter quickly to either location. But, if you are going to run wire, you can use it for the direct voltage-drop measurement anyway, without a switch and with a single wire.
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