Noise suppressing a c phase control system

Claim 2

An a-c phase control circuitry with reduced radio noise including in combination a. an a-c power source; b. a load supplied from said power source; c. a full wave diode rectified bridge having a-c terminals conductively connected to said power source and d-c terminals conductively connected to a power transistor; d. a free running oscillation generator energized by the d-c voltage prevailing between said d-c terminals of said rectifier bridge and controlling rapid ON-OFF switching of said power transistor; e. an auxiliary transistor cascade connected with said power transistor, said cascade connected power transistor and said auxiliaRy transistor being shunted by a capacitor; f. said capacitor and other constituent circuit elements of said circuitry being formed by a monolithic integrated circuit; and g. manually operable means for varying the fraction of each cycle of said power source during which said power source is conductively connected to said load.

Claim 3

An a-c phase control circuitry with reduced radio noise including in combination a. an a-c power source; b. a load supplied from said source; c. a full wave diode rectifier bridge having a-c terminals conductively connected to said power source and d-c terminals conductively connected to a power transistor; d. a free running oscillation generator energized by the d-c voltage prevailing between said d-c terminals of said rectifier bridge and controlling rapid ON-OFF switching of said power transistor, said free running oscillation generator being formed by a capacitor and a unijunction transistor, said unijunction transistor controlling the gate circuit of an auxiliary thyristor to trigger said auxiliary thyristor; e. a capacitor shunted across two electrodes of said power transistor and charged by a voltage depending upon the flow of current through said auxiliary thyristor; and f. manually operable means for varying the fraction of each cycle of said power source during which said power source is conductively connected to said load.

Claim 4

An a-c phase control circuitry with reduced radio noise including in combination a. an a-c power source; b. a load supplied from said source; c. a full wave diode rectifier bridge having a-c terminals conductively connected to said power source and d-c terminals conductively connected to a power transistor; d. a free running oscillation generator energized by the d-c voltage prevailing between said d-c terminals of said rectifier bridge and controlling rapid ON-OFF switching of said power transistor, said free running oscillation generator being formed by a capacitor and a unijunction transistor, said unijunction transistor controlling the gate circuit of an auxiliary thyristor to trigger said auxiliary thyristor; e. a capacitor shunted across two electrodes of said power transistor and charged by a voltage depending upon the flow of current through said auxiliary thyristor; and f. manually operable means for varying the fraction of each cycle of said power source during which said power source is conductively connected to said load.

Claim 5

An a-c phase control circuitry as specified in claim 2 including lead means conductively connecting said d-c terminals of said rectifier bridge, a serially connected resistor and Zener diode providing reduced and stabilized operating voltage for said free running oscillation generator being included in said lead means.

Claim 6

An a-c phase control light dimmer circuitry with reduced radio noise including in combination a. an a-c power source; b. an electric lamp supplied from said power source; c. a power transistor controlling the flow of current from said power source to said electric lamp; d. means for effecting rapid ON-OFF switching of said power transistor including an auxiliary transistor and a capacitor, said auxiliary transistor and said power transistor being cascade connected and said auxiliary transistor and said power transistor being shunted by a capacitor, and said capacitor and other constituent elements of said dimmer circuitry being formed by a monolithic integrated circuit; and e. manually operable means for varying a controlled fraction of each cycle of said power source during which said power source is conductively connected to said electric lamp.

Claim 7

An a-c phase control light dimmer circuitry with reduced radio noise including in combination a. an a-c power source; b. an electric lamp supplied from said power source; c. a power transistor controlling the flow of current from said power source to said electric lamp; d. means for effecting rapid ON-OFF switching of said power transistor including an auxiliary transistor and a capacitor, said auxiliary transistor and said power transistor being cascade connected and said auxiliary transistor and said power transistor being shunted by a capacitor, and said capacitor and other constituent elements of said dimmer circuitry being formed by a monolithic integrated circuit; and e. manually operable means for varying a controlled fraction of each cycle of said power source during which said power source is conductively connected to said electric lamp.