VTVM
Noun
Meaning
VTVM (plural VTVMs)
Initialism of vacuum tube voltmeter.
Examples
A once-popular form of this instrument used a vacuum tube in the amplifier circuit and so was called the vacuum tube voltmeter, or VTVM.
Vacuum Tube Voltmeters or valve voltmeters (VTVM, VVM) were used for voltage measurements in electronic circuits where high impedance was necessary.
The VTVM had a fixed input impedance of typically 1 megohm or more, usually through use of a cathode follower input circuit, and thus did not significantly load the circuit being tested.