Serial No.15565 L101
RCA Solid-State "VoltOhmmyst" Multi range electronic voltmeter model WV-500b. The circuit incorporates 4 transistors and has an input resistance 11 megohms on all voltage ranges. It requires one 1.5volt type c cell and three 9 volt PP3 type batteries [two of which are wired in parallel.] Working, USA, date 1968/9.
This is one of several instruments given to me by Deborah Waters, which belonged to her late father. It has required no attention other than cleaning and a set of batteries.
Interior of the instrument [note that the leads to the cell have to be soldered]
Interior of the instrument [showing the three 9 volt batteries ]
Interior of the instrument [showing calibration adjustment potentiometers]
There are brief instructions on the back of the plastic case.