Television receiver including a beam current limiting circuit
AssigneeU.S. Philips Corporation
InventorsWouter Smeulers, Willem Hendrik Amsen
Life of this patent
Estimating the term…
Abstract
A circuit measures the beam current of a cathode ray tube and derives a control signal from it to prevent overdriving and defocussing of the CRT. The circuit can measure both peak and average values and has an isolation circuit, such as an emitter follower, to prevent loading of the cathode circuit of the CRT.
Claims7
A beam current limiting circuit for a cathode ray display tube having at least one cathode, said circuit comprising an isolation circuit having a high impedance input means for coupling to said cathode and an output, and time constant circuit means for generating a beam current limiting signal in accordance with the cathode beam current having an input coupled to said isolation circuit output and an output means for providing said beam current limiting signal.
Dependencies are inferred from the claim text.