Test Equipment Anonymous

EC8010 wrote: ↑Sun Feb 01, 2026 7:09 pm Very pretty. Shame about the "Kelvin, g, s" legend; it must be American. I have a (very mild) hankering for a torsion wire galvanometer as used at school with its illuminated line moving a glass display.

Yes, that irked me too.

Similarly measuring time in mhos is one of my bugbears. As is measuring frequency in mHz - especially since one of my instruments is careful to distinguish between MHz and mHz on the same results display: 621mHz deviation from 10MHz.
https://www.eevblog.com/forum/testgear/ ... msg3194292

Victor Meldrew is becoming my hero.

Time in mhos? I don't believe it!

I then wracked my brains and remembered that mho was an old-fashioned unit for conductance, but the proper (SI) unit is siemens (S), not seconds (s).

We need Boltzmann's constant (k) to calculate resistor noise, requiring absolute temperature in kelvin (K), and remembering to convert from kilohm (k) when appropriate.

I ought to start referring to capacitance values in Jars. https://en.wikipedia.org/wiki/Jar_(unit)

I wonder if it is coincidence that my recent Sullivan capacitor is up to 1000Jars in 9Jar increments?
viewtopic.php?p=12485#p12485

Pah! I knew instantly what you were talking about when you mentioned Jars. I have both volumes of the "Handbook of Wireless Telegraphy" (1938), I'll have you know.

Before Christmas, Sainsburys had some inverted truncated pyramid tins (shortbread rounds with Belgian chocolate) that had a rather splendid hippy-dippy-trippy pattern. I saw one and decided it was the ideal shape and size for a quiet bench HT regulator. Work is progressing. Top will be fitted with a rather nice Ernest Turner moving coil meter to monitor load current on two ranges (10mA and 30mA). Heatsink for regulator has been drilled and tapped to secure it to tin. Although decorative, biscuit tins tend to need a bit of strengthening, so the bottom has had a plate added and the top too. I have lots of Q-Max punches, but did I have a 62.5mm punch? No. I clamped the 1/8" additional top plate to lathe face plate and bored it to 62.5mm for the meter. Fits nicely.

EC8010 wrote: ↑Tue Feb 10, 2026 11:02 pm
<snip>

I have lots of Q-Max punches, but did I have a 62.5mm punch? No. I clamped the 1/8" additional top plate to lathe face plate and bored it to 62.5mm for the meter. Fits nicely.

Sounds like you need N+1 Q-max punches, specifically one in 62.5mm Ø...

-Pat

I have just looked and found a few gaps in my punches. At the larger end where they're >£50 each. Those punches can't be bought speculatively, only when there's a specific need. And 62.5mm wasn't there, the nearest was 65mm, which I have.