John Richard Wiegand (February 23, 1912 - December 1986)
Brushing Up on Wiegand
- born in Germany, he emigrated to the United States in the 1930s to study music (piano and choral conducting) in New York City. discovered the Wiegand effect The Wiegand effect is a nonlinear magnetic effect, named after its discoverer John R. Wiegand, produced in specially annealed and hardened wire called Wiegand wire.
Wiegand wire is low-carbon Vicalloy, a ferromagnetic alloy of cobalt, iron, and ...
, a physical phenomenon
A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried W ...
in which a special wire, called a "Wiegand wire", produces small magnetic fields. The accompanying Wiegand reader detects the magnetic pulses produced by the two-domain wire embedded within, typically, plastic cards. There is also a Wiegand interface
The Wiegand interface is a de facto wiring standard which arose from the popularity of Wiegand effect card readers in the 1980s. It is commonly used to connect a card swipe mechanism to the rest of an access control system. The sensor in such a ...
commonly used to transmit the data collected by a Wiegand sensor in a card reader. The Wiegand effect was first thought to be a commercially viable solution to better ignition systems for internal combustion engines. Echlin Corporation, an automotive parts manufacturer owned Sensor Engineering of Hamden, Connecticut in the 1970s. That application was displaced by the electronic ignition system.
References
United States Patent 3780313 First Wiegand Pulse Generator
* ttp://www.freepatentsonline.com/4247601.html United States Patent 4247601br>United States Patent 4263523
American physicists
1912 births
1986 deaths
{{US-physicist-stub