I picked this #Westinghouse 54884B #wattmeter standard off eBay many many years ago. While I've never had a chance to test it, it's a beautiful piece of technology from 100 years ago. Read about it on my project blog.

https://wereboar.com/projects/index.php/2024/07/05/the-westinghouse-54884b-watt-hour-meter-standard/

Got word from my landlord that the #PowerUsage is a bit high, so I just bought a #WattMeter to place here in my office to see what the usage of the #server and such is, and if it's high then I'm going to look into making a new #homelab with lower wattage computers.

Coming from #Iceland where the electricity is so cheap it messes a bit with a person's mind and behaviour.

I've restored, repaired and calibrated this neglected Feedback Electronics #WattMeter from the 1980s. It looked like it had been left in someone's back yard for years, though internally as clean as a whistle.

#PowerMeter #TrueRMS #TestGear #TestEquipment #Electronics
[25/01/2020]

What’s in a Wattmeter?

The idea behind watts seems deceptively simple. By definition, a watt is the amount of work done when one ampere of current flows between a potential of one volt. If you think about it, a watt is basically how much work is done by a 1V source across a 1Ω resistor. That's easy to say, but how do you measure it in the real world? [DiodeGoneWild] has the answer in a recent video where he tears a few wattmeters open.

There are plenty of practical concerns. With AC, for example, the phase of the components matters. The first 11 minutes of the video are somewhat of a theory review, but then the cat intervenes and we get to see some actual hardware.

Inside the first wattmeter, he finds essentially the same circuit he was drawing at the start of the video, with some practical additions like range selection. The principle used is slightly different than the one he was drawing, but the core principle is the same: measure the voltage and the current to find the power.

We tend to be a little more cautious around main power, but unlike some other famous YouTubers, he manages not to shock himself or set any fires, at least on camera.

We marvel at the mechanical design of these meters and we also liked the homebrew power meter power strip. So if you like the theory, the teardowns, or a homebrew project, there's something for you.

Measuring power at RF is a whole other science. Naturally, there are many ways to measure wattage, and not every instrument uses the same method.

#teardown #wattmeter

Homebrew Wattmeter Pays Homage to Sturdy Original

If there's one instrument that hams and other radio enthusiasts covet, it's the venerable Bird 43 Thruline wattmeter. The useful RF tool has barely changed in the nearly 70 years since it was first introduced, and they're built like a tank. This makes Bird meters highly desirable, and therefore quite expensive either brand new or on the swap-meet circuit.

But radio amateurs are nothing if not resourceful, and building a homebrew version of the Bird wattmeter (in Portuguese; Google translate tool at the bottom of the page) as Brazilian ham [Luciano Sturaro (PY2BBS)] did is a good way to get your hands on one. Granted, [Luciano] had a head start: a spare line set, which is the important bit from a Bird wattmeter. The machined metal part is in effect an air-insulated section of coaxial cable that the RF signal passes through on its way from transmitter to antenna. A "slug" is inserted into the cavity in the line set to sense the RF and couple it to the meter electronics; the slug can be rotated to measure RF traveling in either direction, allowing the user to determine how much RF is getting reflected by the antenna system.

[Luciano]'s version of the meter is faithful to the sturdy construction of the original, with a solid steel case that mimics its classic lines -- the case even sports the same color scheme and stout leather carry handle. There are some changes to the electronics, and the meter movement itself is different from the original, but all in all, the "Buzz 50" looks fantastic. We especially love the detailed nameplate as an homage to Bird.

The thing about Bird -- and Bird-like -- meters is that the slugs are like potato chips; you can't have just one. Curious as to how these slugs work? Check out this slug repair project.

[Featured image of Bird 43 Wattmeter: Martin RF Supply]

Thanks to [Niko Huenk] for the tip!

#radiohacks #amateurradio #antenna #coax #ham #micoammeter #rf #slug #transmitter #wattmeter