Meters


This is probably the oldest meter I have, used to check A batteries.

These meters were made in Germany, in the 40's.

A Knight-Kit VTVM. Still works great.

The first multimeters were usually 20,000 ohms/volt. This was a measure of how much loading the meter presented to the circuit under test. For each volt full scale selected, the meter represented a load of 20,000 ohms. The 15 volt scale would present a load of 2.1 Megs. The 3 volt scale would be 60,000 ohms.

The VTVM used a tube in a bridge circuit to reduce loading. Most of them had a 10 Meg resistor in the probe, which raised the input impedance almost to a negligible point.

Today's DVM's can do the same thing. You just don't get a cool meter pointer to look at.


This is an old Weston light meter. It's actually rather heavy for it's size.

For the record, this picture was taken with 100 foot-candles of light.

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