Television picture display device
AssigneeU.S. Philips Corporation
InventorsPaulus J. M. Hovens, Wouter Smeulers
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Abstract
In a class-B output amplifier having an npn-transistor the collector of which controls a cathode of a picture display tube via oppositely conducting parts of a diode and an emitter follower, respectively, a signal corresponding with the beam current through the relevant cathode is obtained from the collector circuit of an npn-transistor whose base-emitter path is arranged in parallel with the diode. The signal corresponding with the beam current can be used for controlling a background current and for limiting a beam current, respectively.
Claims5
A television picture display device having a picture display tube, a cathode circuit of which is connected to an output of a video output amplifier, this output being coupled to a collector circuit of a transistor via an emitter follower and a diode, the emitter of the emitter follower and the anode of the diode being connected to the output of the video output amplifier, characterized in that arranged in parallel with the diode there is the base-emitter junction of an npn-transistor the collector circuit of which is connected to an input of a circuit for measuring the beam current of the relevant cathode of the picture display tube and the base of which is connected to the anode of the diode.
Dependencies are inferred from the claim text.