Semiconductor potentiometer

Claim 1

APPARATUS FOR PRODUCING AN OUTPUT REPRESENTING THE PRODUCT OF TWO DIFFERENT FUNCTIONS, SAID APPARATUS COMPRISING A JUNCTION TRANSISTOR HAVING A BASE LAYER INTERPOSED BETWEEN AN EMITTER LAYER AND A COLLECTOR LAYER, SAID BASE AND COLLECTOR LAYERS BEING OF MUCH HIGHER RESISTIVITY THAN SAID EMITTER LAYER, AN OUTPUT CONNECTION NEAR ONE END OF SAID COLLECTOR LAYER, FIRST AND SECOND CONTACTS RESPECTIVELY DISPOSED AT THE OPPOSED ENDS OF THE BASE LAYER WITH THE FIRST CONTACT BEING LOCATED ADJACENT THE OUTPUT CONNECTION, MEANS FOR APPLYING A BIAS BETWEEN THE TWO CONTACTS WITH THE VOLTAGE AT THE FIRST CONTACT BEING AT A LOWER POTENTIAL THAN THE VOLTAGE AT THE SECOND CONTACT, THE SATURATION RESISTANCE OF THE TRANSISTOR BEING A FUNCTION OF THE MAGNITUDE OF THE BIAS APPLIED BETWEEN SAID CONTACTS, MEANS FOR APPLYING AN INPUT SIGNAL ACROSS THE BASE AND EMITTER LAYERS SO THAT THE OUTPUT VOLTAGE AT SAID COLLECTOR CONNECTION IS A FUNCTION BOTH OF THE INPUT SIGNAL AND OF THE MAGNITUDE OF THE BIAS, AND AT LEAST ONE OF SAID LAYERS HAVING A NON-UNIFORM SHAPE TO VARY THE SATURATION RESISTANCE OF THE TRANSISTOR NON-LINEARLY WITH RESPECT TO THE BIAS.