ClipArt ETC
"An instrument for measuring the strength of an electric current in amperes."-Whitney, 1902

Ampere-meter

"An instrument for measuring the strength of an electric current in amperes."-Whitney, 1902

A simple battery or cell used to generate electricity by chemical action.

Simple Battery

A simple battery or cell used to generate electricity by chemical action.

Bijur vibrator voltage regulator.

Bijur

Bijur vibrator voltage regulator.

Section showing Delco Mercury-Bath voltage regulator.

Delco

Section showing Delco Mercury-Bath voltage regulator.

"Compound wound dynamo, used when better automatic regulation of voltage on constant pressure circuits is desired than is possible with the shunt machine." — Hawkins, 1917

Compound wound dynamo

"Compound wound dynamo, used when better automatic regulation of voltage on constant pressure circuits…

An illustration of the foster method, used to measure electric current.

Foster's Method

An illustration of the foster method, used to measure electric current.

Now known as electrostatic generators, the Frictional electric machine produces static electricity at high voltage. "A, glass plate; B, rubber, holding amalgam; C, collecting points; D, prime conductor." -Whitney, 1911

Frictional Electric Machine

Now known as electrostatic generators, the Frictional electric machine produces static electricity at…

An illustration of the loss of charge method.

Loss of Charge Method

An illustration of the loss of charge method.

A potentiometer instrument for measuring the potential (or voltage) in a circuit taps off a fraction of a known voltage from a resistive slide wire and compares it with the unknown voltage by means of a galvanometer. The sliding tap of the potentiometer is adjusted and the galvanometer briefly connected to both the sliding tap and the unknown potential; the deflection of the galvanometer is observed and the sliding tap adjusted until the galvanometer no longer deflects. At that point the galvanometer draws no current from the unknown source, and the magnitude of voltage can be calculated from the position of the sliding contact. This null balance method is a fundamental technique of electrical metrology.

Potentiometer

A potentiometer instrument for measuring the potential (or voltage) in a circuit taps off a fraction…