A good DMM will have an analog section located down under the numbers. This is a analog bar graph and is used like the needle deflection on a old analog meter.The difference is it updates at 40 times a second. No needle can move that fast.
I had a Simpson analog meter bought when I was a teen. And a Heath kit analog meter a neighbor gave me. Both stayed on the shelf after my first quality DMM and they are now in a land fill because they were never used again.
The auto companies banned analog back in the early 80s, right when on board computers showed up. The reason was they would damage sensitive circuits due to the wrong impedance. Slow update rate and general inaccuracy were other factors.
Why are some DMMs more than others? Update rate, features,accuracy and safety. Like a locomotive, you get what you pay for.
A good way to check the accuracy of a DMM is at a A/C wall plug. Switch to Hz and check the frequency. Now reverse the leads and repeat. Since 60 cycles is standard, you should see 60 Hz on both tests. If you see 65 Hz one way and reverse the leads and get 55 Hz, you have a problem. And not with your home wiring.
Do you want to measure capacitance, duty cycle, temperature or high frequency signals? Are features such as MIN/MAX/Average and recording important to you?
If not, then maybe a cheap meter is better for you.
A caution about these harbor freight meters. Stay away from electrical fuse panels. If you are on the upstream side of a fuse panel and a transient hits, like a surge or lighting strike, we may be seeing your layout on ebay.
Jim
Over 50 (Ain't we all?)
Unless you are having control issues then voltage readings are not really necessary. The most important test of your layout, DCC system and wiring is what is referred to as a quarter test. This test will let you know if you have problems and need to correct wiring issues. Most boosters for indoor HO and N scale layouts are two to five amp rated outputs. Placing a metal object across the rails should trip the breaker in the booster immediately. If the breaker does not trip in blink of an eye quick time then there are problems that need to be addressed. Most of the time it is either a bad solder joint or not enough feed wiring and relying on rail joiners to transfer the current. When I am laying rail or wiring a system I use a home made buzzer to check for shorts. Its nothing but a peizo buzzer and 9 volt battery with a couple of alligator clips. Never wire or add track with the system hooked up. Another handy tool is a lighted car or like I have is an old loco truck with a 14 volt light bulb soldered on the pickups. I use this rig to test for dead spots and to make sure my toggles are wired to the right track.
If your really in need to take accurate voltage readings you can either buy a rammp meter or take a voltage reading from a decoders light output. Still voltage will tell very little. Current carrying and how your system responds to shorts is the most important. This current is what caries the digital signal.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
gandydancer19 I remember those old 260's from my Navy days...
I remember those old 260's from my Navy days...
Yup. Me, too. Was stationed at Brunswick Naval Air Station in Maine for two years after graduation from "A" school in Memphis, Tenn (aviation communications and navigation tech 2nd class prior to discharge).
After my 4-year navy hitch I came back home and completed an electrician apprenticeship at a GM parts plant locally and had a Simpson 260 in my maintenance tool box. Darn things were rugged ... and expensive even 50 years ago.
This said, having been in the hobby since the early 70's but just now making the move to DCC with my last new build (retired...sold home of 47 years and moved to a condo) from what I've read related to DCC it came across that DCC is a finicky animal with respect to voltage degradation, thus my question/concern whether a digital-to-the-tenths-of-volt VOM was really a necessity - and the cost. And given the replies here the general answer is NO....with the kicker the accuracy of a $5 Harbor Freight digital will suffice for comparison to an analog VOM.
I remember those old 260's from my Navy days. Use it. I don't see why it wouldn't do what you want it to do. If you just want to see if power is on the track you can even use an automobile tail light bulb. I haven't found anything that I need a real accurate reading for yet on DCC track voltage.
If you want a digital multimeter because it is easier to read, go for it.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
The object of using a meter when you are building/wiring your layout is:
As long as the 'reading' on your cheap Harbor Freight meter is the same at both places(within .1 volts), that is all you need to know. You are just checking to see if you have a loose connection or bad solder joint..
If you really want exact measurements that take in the high frequency DCC signal, then spend money on a RRampMeter.
Modeling BNSF and Milwaukee Road in SW Wisconsin
Digital will be easier to read, and have a higher impendence - less influence on the circuit under test. However, a digital meter can't show rapid changes like a good analog meter can. If you know how to read it, an analog meter will be fine for anything you'd want to do. No need to go buy another meter if you have a good working analog one. However, you also do not need an expensive meter for any model railroad work. The Harbor Freight ones that are usualyl about $3 and sometimes they give them away with a coupon are perfectly adequate for any MRR work.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Over50Once I get my layout wired and ready to run my question is whether a digital VOM is really necessary with DCC vs a standard analog VOM. At 73 (and limited longevity being realistic) I really don't want to spend the money on a good digital multimeter if my analog VOM will suffice with checking track voltage problems if any.
Personally if I am just testing track and getting general ideas, I set the meter to AC and measure away. Doesn't matter if the meter is digital or analog. I've got several of both.
I build one of the $2.99 Harbor Freight Tools digital meters into the track feeds off the electric bus of my modular unit. I can see AMPS increase as the locos approach the feeds on the module and fade away as it moves to the next modules. Do I believe the number given? No not exactly but I know when one loco is a hog and another is a miser.
I have always found that the digital meter was easier to read and interpret with present day electronics.
Your mileage may vary.
The analog were better when I worked with audio and shortwave equipment in the tube days, especially with the center reading analog meters.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
One thing I noticed over the years with D'Arsonval analog meters is the difference when the meter is standing or laying down. Meter impedance I remember was an issue with the older VOM's.
The ones today have a much higher impedance.
Eventually the standing readings can be lower. How much lower, depends on different things. The mechanical movement is affected by age, use, rough treatment. Also, gravity is not just a good idea, it is the law.
My first VOM was a meter I built from Heathkit, about 1954. A few years later an Eico VTVM was better but it eventually had issues with accuracy.
I would be interested in the DCC voltage readings.
In all actuality an analog meter with a sweeping pointer will be more accurate than a digital meter. Remember that DCC is not a true AC wave sign and it is not straight DC either. Some people have called it a clipped AC signal that acts like AC but is not AC. A DVOM reads AC and DC but not the switched pos/neg DC digital sign wave accurately. Your analog sweep meter on an AC setting will more accurately read the quickly switched DC signal due to its slower response.
This is no reason to scrap all of our meters and search E-bay, garage sales and flea markets for analog meters. I have several DVOMs. Not used so much for layout work but instead for decoder installations. For testing layout wiring there is no more important tool than the quarter or some other handy metallic object. This should be the first tool to reach for after wiring some track.
richg1998 If you can work without one, go for it. I have an old Weston in a wood case more for display The cheap ones are much easier to use and read. I am 72 and have been using the $5.00 one from Harbor Freight for some years. I have three of them. They agree with each other. Guess how much they cost to remove if mis-used. I have a Tek Scope and expensive meter for comparisons. The cheap ones measure about 13.6 VAC on my NCE Power Cab. The only ones who disagree are those who do use this meter. Some say not very accurate but the DC power supply for the Cab is about the same. This is model railroading, not rocket science. What some fail to do is look for a trend when troubleshooting DCC on the layout. If the DCC booster says, 16 VAC, then use that as a reference. If you see 12 VAC somewhere, you nave a poor track connection. http://www.harborfreight.com/7-function-digital-multimeter-92020.html http://www.trainelectronics.com/Meter_Workshop/ http://www.trainelectronics.com/Meter_HF/index.htm Rich
If you can work without one, go for it. I have an old Weston in a wood case more for display The cheap ones are much easier to use and read.
I am 72 and have been using the $5.00 one from Harbor Freight for some years. I have three of them. They agree with each other. Guess how much they cost to remove if mis-used.
I have a Tek Scope and expensive meter for comparisons.
The cheap ones measure about 13.6 VAC on my NCE Power Cab. The only ones who disagree are those who do use this meter. Some say not very accurate but the DC power supply for the Cab is about the same. This is model railroading, not rocket science. What some fail to do is look for a trend when troubleshooting DCC on the layout. If the DCC booster says, 16 VAC, then use that as a reference. If you see 12 VAC somewhere, you nave a poor track connection.
http://www.harborfreight.com/7-function-digital-multimeter-92020.html
http://www.trainelectronics.com/Meter_Workshop/
http://www.trainelectronics.com/Meter_HF/index.htm
Cheap is good! Matter of fact I saw the meter you linked on sale at Harbor Freight earlier today but was leery the $5 cost equalled lousy meter/waste of money. Your experience with these cheapie's is good enough for me. Just to mention the VOM I have is a Simpson 260 which in it's day was a top quality VOM - and not cheap by any means.
Really appreciate the confirmation Harbor Freight's throwaway cost digital meter will do the job.
Thanks to richhotrain's suggestion (Monoprice.com link) in a previus post I now have a 100 ft. roll of #14 ga, 4-conductor, 4-color speaker wire to use for my Digitrax DCC and capacitive discharge power supply buss wiring at a major cost savings vs by-the-foot #14 wire from the big box stores.
Once I get my layout wired and ready to run my question is whether a digital VOM is really necessary with DCC vs a standard analog VOM. At 73 (and limited longevity being realistic) I really don't want to spend the money on a good digital multimeter if my analog VOM will suffice with checking track voltage problems if any.