Quote:
Originally Posted by cletrac
Here's another ebay item. It says for 18 set or 19 set but it's dated 1940. It's a military ohm meter for testing batteries I think.
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Oh good grief. £45, really? You can get them for under £5 at radio rallies, usually.
Instrument, Testing, No.1 is a very basic test meter for line telephony and telegraphy use, back in the 1940s. It coexisted (and eventually replaced) the "Detector Q & I" magnetized needle voltage and current detector used on early telegraphy circuits (that was still being manufactured and issued late in WW2).
Q id Quantity (current, I think) and I is Intensity (Voltage), but I may have them backwards.
Anyway; Instrument, Testing No.1 allows voltage and current measurements on field telephone circuits, on-load testing of 'S' and 'X' cells to determine their usability, and approximate low-ish resistance measurements.
For higher voltages (wireless sets) there was the Voltmeter, Pocket, No.2.
There were a couple of less crude and fairly effective military multimeters, plus commercial equipment for higher echelons, and for accurate resistance measurement there was the trusty Post Office Box and a galvanometer, plus dry cell(s) to suit.
Chris.
p.s. there are a couple of others on eBay for less than a quarter of that price, and it's still too much (really) for what they are. (IMAO, YMMV)