The Handy Multimeter

The Digital Multimeter
The digital multimeter.



Highlights:

  • What is a digital multimeter?
  • Who invented the digital multimeter?
  • The digital multimeter measures almost everything but is so compact that you can put it in your pocket.
  • This week in Invisible History: The Great Moon Hoax. Domain: Astronomy.

Today we are going to talk about electronics. Now I use electronics in my day to day life. I have designed many automotive parts which work on electronics, wire harnesses and yes I currently work in a company designing lithium-ion battery packs. But I am not an electronics guy! I just want to be precise. I understand what a resistor is, what it does, and I can give you the waterfall and water pressure analogy of amperes vs volts. But, I am not a guy who can design a complex circuit, and I usually need help with this kind of stuff.

I am not an electronics guy, but I have always worked with the wiring. The moment you work with circuits and wirings, you should be the owner of a multimeter. And it has helped me on numerous occasions while connecting wires. So let's discuss that.

The British Trail

A multimeter is an electronic testing device that combines several measurement functions into one unit. The simplest multimeters measure voltage, current and resistance. Advanced multimeters can also measure capacitance, conductance, frequency, inductance, continuity and temperature. As we know it today, it is a typical handheld device to measure the parameters mentioned before. But it wasn't always like this. The first moving-pointer current-detecting device was the galvanometer in 1820. These were used to measure resistance and voltage by using a Wheatstone bridge circuit and comparing the unknown quantity to a reference voltage or resistance. As a minus point, these were bulky and very delicate.1

The AVOmeter
The first multimeter to measure various things: The AVOmeter.


The development of what we know today as the multimeter is attributed to a British post office engineer named Donald Macadie. He worked in maintaining the telecommunications circuits. He was dissatisfied with the need to carry many separate instruments required for maintenance of these circuits. So in 1923 (almost 100 years after the galvanometer,) he made and developed the multimeter which could do all of it.2 He invented a device which could measure amps, volts and ohms. So the multifunctional meter was then named Avometer. This AVO test meter consisted of a single moving coil meter with a set of switches and precision resistors that enabled it to provide a variety of measurements and ranges.

Root cause analysis

As mentioned above, there are many features that the multimeter can provide. Do you want to test the efficiency of a motor? Get a Multimeter! Want to see if the voltage in your wall is AC or DC? Get a Multimeter! Want to check the traces on a PCB? Get a Multimeter! But the feature that I have used the most in my experience is the continuity.

Multimeter for root cause analysis
Tech. Sgt. Orlando Ortega, the  2nd Medical Support Squadron biomedical equipment maintenance technician, uses a digital multimeter on a computed tomography machine on Barksdale Air Force Base, La., Oct. 25.


When I was in university, and we were building a race car for Formula Student, I was designing the parts for the engine. And this included the wire harness of the whole vehicle. It sounds simple, but it was a nightmare. Imagine the entire team working on the car for a night, and then it doesn't start. The first thing that you check is the wiring. It is the first step to do a root cause analysis. And if you want to check the harness, get a multimeter! Set it up to continuity and listen to that pleasant beep.3 We even understood the circuits of the built-in engine harness using multimeters. Multimeters are awesome!

Your turn now

Imagine being so frustrated with the pieces of equipment that one carries that it lead to an invention superimposing all the instruments. It must take a different level of curiosity and foresight to make a device such as a multimeter. So the next time you deal with a digital multimeter think of the ways you could use it and how it was invented. And if possible, think of some inventions of your own which can combine many instruments and make it simple.

This week in Invisible History

I think the hint behind the last week's history code was a good one with two people giving the right answer. The previous time winner Nikhil Chandratre (WhatsApp) and Commie_Killer76 (Discord.) The last week's code referred to the great balloon "Double Eagle II" which crossed the Atlantic Ocean and landed on 17 August 1978 in Miserey near Paris. It became the first hot air balloon to do so. It was piloted by Ben Abruzzo, Maxie Anderson, and Larry Newman. This article in the National Geographic is an excellent read with many details about the ride.4

Double Eagle II monument
Double Eagle II Monument, Presque Isle, Maine.


The clue for next week is something related to astronomy. The clue is "The Great Moon Hoax." You can actually just google this term and guess the answer. You can write the answers to me in the comment section or on social media. I have left the links down below. If you give the right answer, your name will be mentioned in the next week’s article.

I have been using multimeters for most of my life and have recommended it to many people. But I had never thought the way it was discovered. I once opened up a multimeter to understand the printed circuit board inside the casing. The copper traces and the components used inside are very densely packed. It shows how many functions that this little humble device can do. Also as I mentioned before, look around and appreciate the things you see. And try to make them better. This blog can be a good starting point for the same. To get notifications of new articles follow the blog on social media. I have added the links below.

See you next Saturday! Have a good one!

  1. Reddit:r/theinvisiblegenius
  2. Instagram: @theinvisiblegenius
  3. Twitter: @notnitinchopra

Reference links

  1. "A New Electronic Rectifier", L.O Grondahl & P.H. Geiger, Transactions, American Institution of Electrical Engineers, February 1927 pp. 358–366
  2. Greater London Industrial Archaeology Society
  3. How To Test For Continuity | Fluke
  4. #tbt: The First Successful Balloon Flight Across the Atlantic – National Geographic Education Blog

Comments

  1. Wow , I have used multimeters but never appreciated the tech. And the way it was invented really inspires me to be solution driven rather than being irritated. Great article!

    ReplyDelete
    Replies
    1. Hey Sachid!
      Thanks! I am happy that this article inspired you.

      Delete

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