Submitted by Don Grove, North Fork History Group
NORTH FORK — This very old tool was donated to the North Fork History Group. It has a gauge on it marked as amperes. It was proudly made in the USA, so you know it is pretty old.
We know this is an amp meter, but we would like to know how this particular meter was used and anything our viewers can tell us about this tool.
In case you missed it: History Mystery #116: Sam “Long Knife” Clark
What exactly is an amp meter?
An ammeter, also known as an amp meter, is an instrument used to measure electric current in a circuit. It works by connecting in series with the circuit so that the entire current flows through it.
The ammeter contains a calibrated coil, which generates a magnetic field when the current flows through it. This magnetic field causes a pointer or a digital display to move, indicating the amount of current flowing through the circuit.
Ammeters are designed to have very low resistance, so they do not significantly affect the current being measured. Therefore, they must be connected in series with the circuit under test and never directly across the voltage source, as doing so would create a short circuit.
It’s essential to use an appropriate range of an ammeter to measure the current accurately. Using an ammeter with a lower range than the current in the circuit will damage the ammeter, while using an ammeter with a higher range than the current in the circuit will result in lower accuracy.
# 117 THE TOOL IS A BATTERY LOAD TESTER, USED TO PUT A LOAD ON THE BATTERY TO TEST IT