John R. Wiegand

John Richard Wiegand (born 1912, Germany)^[1] discovered the Wiegand effect, a physical phenomenon in which a special wire, called a "Wiegand wire", can detect small magnetic fields. The Wiegand wire is commonly used as a sensor to read security access cards. There is also a Wiegand interface 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

1. Brushing Up on Wiegand - he emigrated to the United States in the 1930s to study music (piano and choral conducting) in New York City.

• United States Patent 3780313 First Wiegand Pulse Generator
• United States Patent 3892118 Where it all Started July 1, 1975
• United States Patent 4247601
• United States Patent 4263523
• United States Patent 4484090
• United States Patent 4309628