Analog meter VS a DMM?

[w2aew]

Agreed, certainly there are limits to how small of a change is noticable with an analog movement, but it is generally better than the resolution of a segmented bar-graph.  Also agreed that manually selecting a range on a DMM will avoid the range changing on the sweep - but this implies a slightly more educated user as opposed to a student. 

One more minor advantage with the analog meters, under some circumstances the inertia of the meter movement can provide a bit of dampening of a noisy measurement that might be difficult to observe on a DMM.

Of course, most of the time I'll use my DMM, but I occasionally find good use cases for my old 260 VOM. And, I fully agree that students should be taught how to use BOTH and to understand the advantages of each.

[rsjsouza]

Agree with w2aew in all accounts. Regarding resolution, comon bargraphs are only 40 or 60 segments and do not have the natual filtering of the mechanical needle - something needed in the example I sent before.
 

[Resistoid]

You asked about good analogue meters. Over in the UK, at least, the Avometer was considered to be the "Rolls-Royce" of these devices:

http://www.megger.com/uk/Products/ProductDetails.php?ID=302&Description=avometer%20model%208

More details here:

http://www.megger.com/common/documents/MOD8_MK7_DS_en_V11.pdf

- You can find various models / mark numbers on Ebay at quite reasonable prices these days.

Resistoid.

[ivan747]

Modern high-end multimeters like the Agilents Dave has have a low pass filter option, so you can overcome noise in your measurements. As far as I know DMMs take several samples and average then before displaying so that, combined with the LPF and the analog bargraph gives you all you needed in an analog meter. There's also a low impedance mode if you need to get rid of stray voltages induced in large coils and such.

And by the way, no one's going to rely on the analog bar graph resolution to make measurements, you use the digital display. If noise is an issue, turn in the LPF.

Sure, these are more expensive than used analog meters, but so are high-end scopes vs. used CROs. High-end scopes imitate the CRT of an analog scope with intensity grading and have a lot of added benefits, just like high-end DMMs vs. analog meters.

[vk6zgo]

Although bargraphs may be able to imitate analog meters,they usually have a lag,so that adjusting a voltage or current value becomes more difficult.

For "peaking" tuning or similar,I usually use an Oscilloscope,either reading signal levels directly,or if there is an associated DC voltage change,as a DC voltmeter.

[KJDS]

You asked about good analogue meters. Over in the UK, at least, the Avometer was considered to be the "Rolls-Royce" of these devices:

http://www.megger.com/uk/Products/ProductDetails.php?ID=302&Description=avometer%20model%208

More details here:

http://www.megger.com/common/documents/MOD8_MK7_DS_en_V11.pdf

- You can find various models / mark numbers on Ebay at quite reasonable prices these days.

Resistoid.

Earlier today I tested three AVO 8 meters. I tweaked a power supply until the AVO read 3V exactly. I also had a 6.5 digit Keithley 2015THD measure the same reading. The 2015 showed 2.998V, 3.006 and 3.008V

They really are a fine bit of kit. I think there's about 2mV resolution on the 3V range.

[Resistoid]

@ KJDS - agreed, excellent gear. It's a real pity Megger have ceased production.

So far as I recall, the Model 8 Mark VII was being sold new for about £700, (or £900 if you bought from RS Components), before the end. - Now secondhand ones can be had much more cheaply.

I own a couple of Model 8 Mark Vs and wouldn't part with them for anything.

Resistoid.

 

[NiHaoMike]

An analog meter would most likely be better for testing the resistance of contactor and relay contacts, because its short circuit current flow is substantially higher than a DMM.  As an example, my Agilent U1272A puts out about 640 microamps, as measured by my Fluke 189.  According to the data sheet, a Simpson 260 puts out 125 milliamps on the RX1 scale.  There are some situations, such as relay contacts, where you actually want to 'stress' the connection.  A DMM, with its miniscule current flow, may be harder pressed to give a true and definitive reading in such situations.

At such low resistances, you'll really need a 4 wire measurement. It's possible to make an analog meter with 4 wire resistance measurement, but in practice, I've only seen digital meters with 4 wire resistance measurement.

Technically, a digital bargraph can respond faster than an analog meter since it doesn't have inertia. The low impedance is useful in a few cases, but they make digital meters with that as well. The auto ranging on digital meters can be annoying, but any good meter lets you turn that off.

An advantage analog meters still have is that they don't need a battery to measure voltage or current. While that's possible for a digital meter, I have not seen one that does. (That would obviously make it no longer high impedance, so add a switch to disable that feature and use batteries just like a normal meter.)

[vk6zgo]

Most bargraphs I've seen "dither"when confronted by a signal which is part way between two steps.

Obviously,they can be, & are, made in forms that do better,but not commonly.
Or the "bargraph" can be be replaced with a simulated analog meter.

Top end Amateur Radio Transceivers have digital display based "S meters" which are indistinguishable from a real meter---they even have the same inertia characteristics as specified for a mechanical meter in the same service.
But these are part of a generally very sophisticated device,& are not cheap!

High impedance isn't just available with DMMs--Old style VTVMs,& the later FET based meters have similar input Z,as does an analog 'scope (with a x10 probe).
As I implied before,such a 'scope in the DC input mode,& with the triggering set to"AUTO,makes a useful large scale DC voltmeter.

Back in the day,4 wire measurement was done with analog meters,as they were the only game in town!

[madshaman]

I love my old Simpson 260. Standard in the industry for 30-40? years.

Thanks for the recommendation, and also those of others!

When I started as a kid, all I had was a hand me down analog meter (whose brand I don't even remember) and an ancient health kit scope built out of tubes from my grandfather.

Don't have an analog meter anymore, my childhood equipment and projects are long gone due to unfortunate circumstances, but I think I'll pick one up!

You might want to take a close look at http://simpson260.com/ for buying a used one, as it sorts out the differences between the revisions and models.

Simpson still makes them though, so there's that option as well.   

Thanks man!  Been distracted from the forum by the fairer sex for a bit (I know, for shame, but she digs my lab anyway ;p).  I'm halfway committed to getting a new Simpson 270-5RT with leather carry case.