VOM Vs. DMM

Reloadron

Joined Jan 15, 2015
7,501
Down memory lane. My first experiences were with a RCA Voltohmyst late 50s early 60s on my father's bench. He taught me how to use it and read it. My later experiences later included the ANUSM 116 VTVM. I still have and use a few old Simpson 260 and a Simpson 269. The latter is just an ohmmeter. I choose a meter like most people, based on my application at the time. The old ANUSM 116 was a pretty interesting VTVM in that the AC probe used a peanut rectifier tube in the actual probe so grabbing the fat AC probe the probe body was always warm. :)

Ron
 

tautech

Joined Oct 8, 2019
383
LoZ is an important requirement for a large portion of the professional meter buying community called electricians.
Even HF has a model with it.
https://www.harborfreight.com/dm1000-electricians-hvac-contractor-trms-multimeter-64019.html
  • LoZ low input impedance: helps prevent false readings due to ghost voltage
Very well aware of this and several decades back before such meters became commonplace our sparky was very aware of ghost voltages and checked everything with a 100W lightbulb with leads attached rather than use his DMM to know a fuse board was dead or power sockets were alive.
Today those of us that do repairs to mains powered appliances/equipment use a dim bulb tester to indicate shorts or normal DUT behaviour.
 

nsaspook

Joined Aug 27, 2009
13,079
Very well aware of this and several decades back before such meters became commonplace our sparky was very aware of ghost voltages and checked everything with a 100W lightbulb with leads attached rather than use his DMM to know a fuse board was dead or power sockets were alive.
Today those of us that do repairs to mains powered appliances/equipment use a dim bulb tester to indicate shorts or normal DUT behaviour.
Well, our industrialist electricians use actual calibrated meters per safety and quality regulations.
 

Ya’akov

Joined Jan 27, 2019
9,069
Down memory lane. My first experiences were with a RCA Voltohmyst late 50s early 60s on my father's bench. He taught me how to use it and read it. My later experiences later included the ANUSM 116 VTVM. I still have and use a few old Simpson 260 and a Simpson 269. The latter is just an ohmmeter. I choose a meter like most people, based on my application at the time. The old ANUSM 116 was a pretty interesting VTVM in that the AC probe used a peanut rectifier tube in the actual probe so grabbing the fat AC probe the probe body was always warm. :)

Ron
I surely remember the Voltohmyst, but it was vintage gear by the time I encountered it. Of course, that meant something different in the early 70s than it means today. It was still considered viable and desirable, just older.

And I do remember the distinctive probe as well. You could tell right away that a meter was a VTVM by it.
 

Ya’akov

Joined Jan 27, 2019
9,069
Well, our industrialist electricians use actual calibrated meters per safety and quality regulations.
Here, electricians used “Wiggys”, solenoid based testers. They provide a load, so no problem with phantoms, and they are rugged as heck. Just like “bandaids” are adhesive bandages, no matter who made them, and “kleins” are linesman’s pliers even if not from Klein, a ”wiggy” was a solenoid tester even if not made by Wiggy.

1685060118453.png
Most electricians really didn’t need more than a wiggy, most of the time. I’ve seen “solid state wiggys” which use progressive LEDs in a wiggy-like form factor but it’s not the same. Wiggys were beasts, with sone serious heft.

I have what I suppose is the evolutionary successor of the Wiggy–a Fluke T5-600, which is far more comprehensive with a kind of fork version of a clamp meter up to 100A, volts up to 600 with a Cat III 600V rating, resistance to 1000Ω, and a continuity beeper.

1685060747788.jpeg
 

Reloadron

Joined Jan 15, 2015
7,501
Sure, they (our guys) used calibrated and checked analog meters decades ago.
During earlier days before digital meters the guys working calibration were referred to as "needle benders". This as if they bent the needles to achieve calibration. I did have the pleasure of working with plenty of analog meters and some really good ones. When I was much younger I worked with many older metrologist who taught me how to use the little counter weights on the meter movement, it was about balance. When a meter was properly calibrated and the counter weights all set you could rotate the meter in any direction and the needle should remain on zero. You test it and turn it turning it on every axis and the needle should remain at the same point.

Ron
 

panic mode

Joined Oct 10, 2011
2,715
"Everyone knows that 3rd digit is superfluous." seem to be tongue in cheek, possibly alluding to"640k ought to be enough for everyone"
 
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