If you’ve ever dealt with RF circuits, you probably have run into Q — a dimensionless number that indicates the ratio of reactance to resistance. If you ever wanted to measure Q, you could do worse ...

This instrument determines the Q (quality factor) of a resonant circuit, crystal, or resonator by measuring its series resistance at the resonance frequency. The Q is linked to the series resistance ...

While LCR meters are readily available at reasonable cost, they do not measure the Q of an inductor. This circuit enables you to measure the Q of inductors with the aid of an RF signal generator. A ...

[Thomas] picked up a Marconi TF1245 with dents and dings. We have to admit that we had not heard of a “circuit magnification meter,” but apparently, this was a thing in the late 1960s and early 1970s.