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US 4,227,098 AGranted
Solid state relay
AssigneeGeneral Electric Company
InventorsDale M. Brown, Marvin Garfinkel, John A. Laurent
Life of this patent
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Abstract
A solid state relay having a light-emitting diode, an array of series connected photodiodes and a field effect transistor is described. The light-emitting diode is optically coupled to the array of photodiodes. The conductive state of the transistor is determined entirely by the voltage developed by the array of photodiodes.
Claims9
A solid state relay comprising
- a pair of input terminals,
- a light-emitting diode connecting to said input terminals for generating radiation in response to current applied to said input terminals,
- an array of photodiodes series connected between a pair of array electrodes and optically coupled to said light-emitting diode for developing a control voltage across said array electrodes in response to radiation from said light-emitting diode,
- a field effect transistor including a pair of current carrying electrodes, a gate electrode and a substrate electrode, one of said array electrodes connected to said gate electrode and the other of said array electrodes connected to said substrate electrode whereby the impedance between said current carrying electrodes has one value in the absence of, and another greatly different value in the presence of said control voltage between said gate electrode and said substrate electrode,
- means for providing a large resistive impedance between said gate electrode and said substrate electrode,
- a pair of output terminals, each connected to a respective one of said current carrying electrodes.
3 more elements
Dependencies are inferred from the claim text.