Re: Test equipment for valve radio repair
Valve voltmeters such as the Heathkit V7A have an input resistance of 11meg ohms, 10meg in the input attenuator chain and another 1meg in the probe tip to minimise capacitive loading in the circuit under test.
Electrometers, where the input goes directly to the grid of the first valve, can have a much higher input impedance, but I guess they can't handle high voltges
S
|