VOMS: Analog Volt-Ohm Meters
Choosing & Using a VOM to Detect or Measure Electrical Voltage or Electrical Resistance & Other Values

Analog Volt-ohm meters (VOMs):

This article describes analog or needle and dial type VOMS, volt-ohm meters used to detect or measure voltage, resistance and values.

VOMs: analog type Volt-Ohm Meters

An analog volt-ohm meter or VOM is a multi-purpose electrical test instrument that can measure AC or DC voltage, resistance (ohms), and depending on the model current (amps).

Some VOMs can also measure sound levels (decibels) or other metrics using an appropriate attachment.

The display on an analog VOM uses a needle or pointer that rotates over display values in an arc. You can see an example of a analog display in the VOM shown at above left. That meter includes a clamp-on ammeter for measuring current. Below is a Simpson analog VOM that has been in use since 1958.

Watch out: If the VOM user is not trained in safe use of this equipment s/he should never insert any instrument or tool into electrical equipment.

See SAFETY for ELECTRICAL INSPECTORS

What's the difference between a digital multimeter (DMM) and an analog VOM or volt-ohm meter? We described VOMs just above. A digital multimeter (DMM) is a multi-purpose electrical test instrument that can measure AC or DC voltage, resistance (ohms), current (amps) and often other conditions such as sound level (decibels) or temperature by using additional sensors or probes.

The display on a digital multimeter is just that - digital, using an electronically-generated number corresponding to the range at which the DMM is set. An example of a digital multimeter is shown just belowk the display window of a Sperry DSA-500.

At DMM DIGITAL MULTIMETER HOW TO USE we explain the function and level settings and probe connections needed when using a VOM or DMM to measure voltage (as well as when measuring current or resistance).

Analog VOMs - Volt-Ohm-Milliameters

A VOM or volt-ohm meter may also be found in an analog form such as our favorite and now a collectors-item little Jensen VOM that we've used for nearly 30 years. Here our photo shows the Jensen analog VOM with its probes attached but not connected to anything.

In 30 years of use we needed one repair of this instrument - an internal fuse which we couldn't find locally. In analog VOMs such as this unit there is typically a very low-amperage fuse whose function is to protect the meter movement from damage.

On contacting Jensen Corporation, the company kindly sent us a few spare fuses. The total repair bill? $0.00.

This little VOM, ca 1985, is about 1/8 the size of the Simpson 260, ca 1958, described just below.

Simpson produces a wide range of test instruments including analog VOMs that can be used to measure resistance (ohms), direct current, alternating current, and even decibels.

See DMM DIGITAL MULTIMETER HOW TO USE for a separate discussion of digital multimeters and VOMs.

Reader Question: Speco F-70 analog VOM meter

27 Feb 2015 weldon said:

Where may I find wiring diagram for Speco F-70 analog VOM meter.

Reply:

Weldon, you can contact Speco Technologies at:

Speco Technologies, 200 New Highway, Amityville NY 11701 Tel: 1-800-645-5516

Currently, in addition to a range of analog VOM Multimeters, Speco produces a wide range of products besides your Speco analog VOM, including digital video recorders, secuity cameras, wireless microphones.

Unfortunately the company's technical support and contact information "... is available to authorized deales only. Contact your installe for questions regarding your Speco products."

The current product line includes an F-72 20K Ohm/Volt VOM Multimeter (shown at above-left) similar to your older F-70. If the company is unable to provide you with a wiring diagram for your Speco F-70 VOM I'd check with some of their distributors such as

Christy Industries at 800-472-2078 in the U.S.

Simpson Analog VOMs

Simpson produces a wide range of test instruments including analog VOMs that can be used to measure resistance (ohms), direct current, alternating current, and even decibels.

Shown here is the Simpson Model 260 Series III Volt-Ohm Milliammeter produced ca 1958 and in use by its owner Paul Galow since ca 1959. This VOM is much larger than the compact devices in wide use today, having a meter display width of 4 1/2".

The device is also quite durable. Mr. Galow reports having to perform two maintenance chores on the instrument, replacing a battery and replacing a soldered-in-place fuse [image] hose function is the protection of the meter movement.

Watch out: don't confuse a volt-ohm-milliameter with clamp-on ammeteres (described next). The Amps measurement range of this Simpson Model 250 VOM is 1MA to 500MA - not at all in the range of household appliances or larger equipment. For higher ampacity measurements you will need an ammeter such as the device described just below.

See this circuit diagram [image] of the Simpson 260 VOM.

See DMMs VOMs SAFE USE OF for safety procedures that also apply to use of VOMs

Where to Buy a DMM or VOM
List of Electrical Test Instruments, VOMs, DMMs, Voltage Detectors: Manufacturers & Sources

• Actron DMMs & VOMs, Website: http://www.actron.com/
• ALL-SUN/e-sun ; Model Number: EM3212 Pen type mini portable Voltmeter Ohmmeter Ammeter pocket-size digital multimeters - [Check for suitable precision and accuracy in low range amps measurement applications]
• ExTech DMMs & VOMs, ExTech Corp. a FLIR company, Extech Instruments Corporation, 9 Townsend West, Nashua, NH 03063, U.S.A., Email: support@extech.com, Tel: 877-239-8324 Option 3, Website: http://www.extech.com
• Fluke Corporation, 6920 Seaway Blvd, Everett, WA 98203, USA, PO Box 9090 Everett, Washington 98206, Tel: +1(425) 347-6100, Technical support: 1(800) 44-FLUKE (1(800) 443-5853), Website: www.fluke.com,
  Fluke Europe B.V, PO Box 1186 Eindhoven, The Netherlands, Tel: +31 (0)40 2 675 200 +31 (0)40 2 675 222, Website: www.fluke.eu
• Fluke India: TTL India Pvt. Ltd. (A Fluke Company), Deodhar Center, 424, Marol Maroshi Road, Andheri (E), Mumbai, 400076, Tel: 1 800 209 9110, Email: info.india@fluke.com, Website: http://www.fluke.com/fluke/inen/products/Digital-Multimeters.htm
• Digital 287/289 Digital Multimeter, Users Manual, retrieved 9/5/21, original source: http://assets.fluke.com/manuals/287_289_umeng0200.pdf, [copy on file as Fluke_287_289_umeng0200.pdf]
• Gowe® Multifunctional Portable Mini Oscilloscope+multimeter (Voltmeter Ohmmeter Capacitance Tester) Handheld Digital Scopemeter - [Check for suitable precision and accuracy in low range amps measurement applications]
• Jensen VOMs, no longer available
• Mastech VOMs and DMMs (made in China), Shanghai Hihua V&A Instrument Company, 881 Ye Cheng Road Jia Ding District, Shanghai 201821, China, Email: mastech@vip.sina.com, Tel: +86 21 69523164　+86 21 69523225, Website: http://www.mastech.com.cn/
• Seaward U.K., Bracken Hill, Southwest Industrial Estate, Peterlee, County Durham, SR8 2SW, United Kingdom, Tel: 44 0 191 586 3511, Fax: 044-191-586-0277, Email: enquiry@seaward.co.uk , Website: www.seaward.co.uk
  
  Seaward Group USA 6304 Benjamin Road, Suite 506, Tampa FL 33634, Tel: 001 (813) 886 2775, Email: sales@seaward-groupusa.com , Website: http://www.seaward-groupusa.com,
• Simpson Electric, P.O. Box 99, 520 Simpson Avenue, Lac du Flambeau, WI 54538-0099 Tel: 715-588-3311, customer service: 715-588-3947, Email: support@simpsonelectric.com, Website: www.simpsonelectric.com/
• Simpson 260® Series 6XLM Volt-Ohm-Milliammeter Instruction Manual, retrieved 9/5/2012, original source: http://www.simpsonelectric.com/uploads/File/datasheets/260-6xlm.pdf, [copy on file as Simpson_260-6xlm.pdf]
• Speco Technologies, 200 New Highway, Amityville NY 11701 Tel: 1-800-645-5516 - Analog VOMs
• T.D. Instruments Corporation, The MINI AMMETER used for adjusting thermostats to work precisely (shown at the top of this page) was produced by and may still be available from T.D. Instruments Corporation, 180 Charlotte St., Rochester, NY 14067 - 716-232-4208. We used model T.D. 2, which operates between 0 and 1.2 Amps A.C. If this instrument is not available look for an ammeter capable of operating with precision in the same very low-end range of current draw from 0 - 2 Amps.

...

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-10-06 by (mod) - manual or instructions for the Speco SA-1000 VOM

Bryan:

I can't say if your VOM is working properly or not, though in my own experience, if the VOM hasn't been dropped or soaked and corroded internally it'll usually work;
Try cleaning the battery terminals and then buying new batteries that match the specs of the ones you remove.

I looked for a manual for this old VOM and didn't find one, but they're pretty standard.

Download a couple of the VOM manuals provided above - they're provided as PDF files at no cost - and review the interpretation of the scales in your meter, the dial settings,and the connection jacks - yours will match nearly all of the others in those manuals.

Below you'll find other postings that give the meter specifications.

The Speco multitester was sold by Component Specialties, Inc. 39 St. Mary's Place, Freeport LI NY

On 2020-10-06 - by (mod) -

Re-posting with image

Bryan Logie said:

I just purchased an old Speco SA-1000 for just $12. While a little rough on the outside, the interior is in surprisingly good condition. Almost fresh from the factory, in fact. There's just one wire that has come loose from a poor solder connection. You can actually see the very unit I have [below] speco-model-sa-1000-300v-ohm-milliamp-meter

I'm trying to find a manual or at least information about the unit. It looks like it can take up to 3 batteries.

There was one battery that looks fairly old (and, again, in almost mint condition) that has zero charge. While I can likely find a replacement for the one battery, I'm curious if the other two (different sized) are required, optional, or maybe just there in case you don't have access to certain batteries.

I would also just like to know a bit more about the functionality of the unit. Anyway, if anyone can help, it would be greatly appreciated! Take care! :)

On 2017-04-05 - by (mod) -

Speco multimeter f 72 is widely available form electrical suppliers and test equipment suppliers as well as online

F-72- 20k Ohms/Volt Deluxe VOM Multimeter

The 20 kohm/volt deluxe VOM multimeter has a battery test, mirrored scale, and tests popular 1 1/2 volt and 9 volt batteries .

It features 7 functions with 23 ranges. Test probes, instruction manual and carrying case are included.

Technical Specifications
DC-Volts 25, 10, 50, 500,1000V
AC-Volts 10, 50, 250,1000V
DC-Current 5mA, 50mA, 10A
AC-Current N/A
Resistance 10K, 100K,10MEG
Battery Test 1.5V, 9V
Decibels -8dB to +62dB in 4 ranges
Audible Continuity

Here at InspectApedia.com, to protect the trust of our readers, we do not sell anything. No products, no services.

On 2017-04-05 by rahimuddin

speco multymeter f 72

On 2016-11-23 - by (mod) -

Michael:

The Speco multitester was sold by Component Specialties, Inc. 39 St. Mary's Place, Freeport LI NY in the US, but the battery won't be a one-off.

Take out the existing battery, photograph its size, voltage, markings, and it should be pretty easy to find a replacement. Or you can use the page bottom or top CONTACT link to send me images.

On 2016-11-23 by Michael

Where can I find a 15 v.dry battery for a speco model f-70

On 2016-07-07 by (mod) - Simpson 260 meter internal fuses

Yes, Kenneth, Simpsons have an internal fuse.

Older models actually had a fuse soldered in place while later models used clips. Open the meter and you'll probably see the fuse and thus be able to match it and replace it.

Of course, first check the meter's batteries.

On 2016-07-07 by Kenneth

Are there any fuses in my Simpson 260 meter. It reads voltage but the ohm quit working?

...

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