Andre-Marie Ampere
Michael Faraday
Friedrich Koepe

Georg Ohm
Elisha Otis
Frank A. Perret
• Jesse Reno
The Siemens Brothers
Frank J. Sprague
Nikola Tesla
Otis Tufts
Alessandro Volta
James Watt



Alessandro Volta
(17451827)

Italian physicist, known for his pioneering work in electricity. Volta was born in Como and educated in the public schools there. In 1774 he became professor of physics at the Royal School in Como, and in the following year he devised the electrophorus, an instrument that produced charges of static electricity. In 177677 he applied himself to chemistry, studying atmospheric electricity and devising experiments such as the ignition of gases by an electric spark in a closed vessel. In 1779 he became professor of physics at the University of Pavia, a chair he occupied for 25 years. By 1800 he had developed the so-called voltaic pile, a forerunner of the electric battery, which produced a steady stream of electricity. In honor of his work in the field of electricity, Napoleon made him a count in 1801. The electrical unit known as the Volt was named in his honor.

The Force of Current

In honor of Alessandro Volta, who sometimes judged a battery by the flash he saw as he touched its wires to his eyelids, electric force is now measured in volts. Voltage is a measure of the electrical "pressure" with which current flows through a wire. This potential is akin to that of water stored in a high tank, ready to pour down through a pipe. The farther water drops down a pipe, the greater will be the pressure of its spurt from a spigot. Similarly, the greater the voltage of a battery, the greater will be the force of current produced.