Arrangements for tuning a receiver

Claim 1

A circuit for applying a tuning voltage to at least one voltage controlled reactance element, said circuit comprising a plurality of activatible circuits each comprising an operable signalling device; a bistable trigger circuit having an operating state and a substantially zero current rest state, said trigger circuit comprising a four layer semiconductor having an emitter electrode adapted to be coupled to a first terminal of a voltage supply, a base electrode coupled to said signalling device for setting said trigger circuit into said operating state upon operation of said signalling device, an anode electrode means for conducting current when said trigger circuit is in said operating state and substantially no current when in said rest state, and a collector electrode; adjustable potentiometer means adapted to be coupled across a second voltage supply and between saId collector electrode and said element for providing said tuning voltage to said element upon activiation of said respective activatible circuit; and locking means for setting and keeping the remaining activatible circuits in said rest state when one of said trigger circuits is set into said operating state comprising a parallel circuit including and a resistor and a capacitor coupled to said anode, and a resistor common to all of said activatible circuits having one end coupled to said parallel circuit and a remaining end adapted to be coupled to the second terminal of said voltage supply source.