High voltage protection circuit

Claim 2

A high voltage protection circuit for a television receiver, comprising: a voltage source representative of kinescope ultor voltage in said receiver; switch means coupled to said voltage source and operable from a first to a second state in response to said voltage source exceeding a predetermined level; a deflection rate oscillator means; circuit means including a capacitor coupling said switch means to said deflection rate oscillator means such that in response to said second state of said switch means said capacitor is charged, thereby disabling said oscillator means.

Claim 3

A high voltage protection circuit according to claim 1 wherein said circuit includes a source of video signals and a blanking means coupled to said source of video signals and said oscillator means, said blanking means being responsive to said disabled condition of said oscillator for blanking said video signals.

Claim 4

A high voltage protection circuit according to claim 2 wherein said switch means includes a unijunction transistor having its gate electrode coupled to a source of reference potential such that when said voltage source exceeds said reference potential said switch means operates to its second state and said capacitor is charged from said source of reference potential.

Claim 5

A high voltage protection circuit for a television receiver for rendering the kinescope raster unviewable when the ultor voltage exceeds a predetermined level, comprising: a source of voltage representative of said ultor voltage level; switching means coupled to said voltage source for switching from a first to a second state when said voltage level exceeds a predetermined level; circuit means including a capacitor coupled to said switching means for charging said capacitor when said switching means is in said second state; a vertical deflection rate astable multivibrator including two active current conducting devices coupled to said circuit means including said capacitor such that when said switching means is in said second state the charge on said capacitor prevents said multivibrator from oscillating and causes one of said active devices to conduct a steady state current; and video blanking means coupled to a source of video signals and to said one active device and responsive to said steady state current for blanking said video signals when said switching means is in said second state.

Claim 6

A high voltage protection circuit for a television receiver for rendering the kinescope raster unviewable when the ultor voltage exceeds a predetermined level, comprising: a source of voltage representative of said ultor voltage level; switching means coupled to said voltage source for switching from a first to a second state when said voltage level exceeds a predetermined level; circuit means including a capacitor coupled to said switching means for charging said capacitor when said switching means is in said second state; a vertical deflection rate astable multivibrator including two active current conducting devices coupled to said circuit means including said capacitor such that when said switching means is in said second state the charge on said capacitor prevents said multivibrator from oscillating and causes one of said active devices to conduct a steady state current; and video blanking means coupled to a source of video signals and to said one active device and responsive to said steady state current for blanking said video signals when said switching means is in said second state.

Claim 7

A high voltage protectiOn circuit according to claim 4 including a source of reference potential and wherein said switching means includes a unijunction transistor having a gate electrode coupled to said source of reference potential such that when said source of voltage exceeds said reference potential said unijunction transistor conducts and charges said capacitor from said source of reference potential.