One of the safest ways to measure current is with a clamp. Clamps do not require you to break the circuit and they safely measure wires with thousands of amps. In this video, we measure DC current in the lab, AC current of a reflow oven controller, and the DC current in a car using a Tenma 72-7226 True RMS Clamp Meter.
This video was the last one I did before moving to a new house / lab.
Chances are, you have used the continuity mode of your digital multimeter. But how much do you understand about how it works? In this video, we break down how the mode works, what the beep means, and show examples of how to use it (correctly.) It might seem silly to spend so much time on such a simple mode.
However, I have run across a few posts on the Internet, including the element14 Community where people do not understand continuity mode. Sometimes it is just a lack of experience and sometimes it is a total lack of understanding of what is happening. The biggest mistake, of course, is trying to measure continuity on a powered circuit. That is just a no-go. So in this video, I wanted to show what the meter is actually doing, how it sees different components, and give a couple of real-life examples of how to use it.
For fifteen years I used my Radio Shack 22-168A digital multimeter as my go-to meter. A couple of years ago I bought a Fluke 115. Not because the RS meter lacked a measurement, but because I wanted a backlit screen. Here’s the crazy thing though in 20 years of multimeter development, there hasn’t been much innovation. Well outside of maybe auto-ranging.
All three meters I have, plus the Virtual Bench I reviewed about a year ago all continue to have the same limitation: they can only perform one measurement at a time. That’s one feature that makes my latest meter, the Mooshimeter, unique. It can measure both voltage and current at the same time. Oh, and it doesn’t have a screen.
A couple of weeks ago, I asked my subscribers for their favorite test equipment alternatives. The reason I asked, was because I recently picked up a Mooshimeter. It is a modern take on the multimeter. However, I will cover that in more detail soon.
While I am fortunate that my bench has the usual equipment like an adjustable power supply, oscilloscope, multimeter, and function generator, I know that not everyone else does. I also had to think back to before I had this equipment, what did I use to troubleshoot my circuits.
Sometimes when working on a project, whether hobby or professional, you just don’t have the tools you need on hand. Or worse, you cannot afford it. So here are some of the responses you all sent me.
Martin Rowe over at Test & Measurement World published an article quite some time ago (1994) that explains what it means when a DMM claims to have “½” digits in their display. Intuitively, to me anyway, when I heard this I always thought of gas-pumps and how we pay for 9/10 of a penny with every gallon of gas (in the United States).
Check out Martin’s post: What’s a half digit, anyway?
