Circuit for the cut off regulation in a television receiver rendered momentarily operative in response to a predetermined operating condition

摘要

A circuit for automatically adjusting the beam current of a CRT to compensate for long term changes in the characteristics of the CRT upon the occurrence of an operational event of the CRT, and for avoiding producing unwanted lines in dark screen areas during current blanking includes an adjustment circuit for providing a reference control signal. A test line generator provides a test line pulse to the adjustment circuit upon the occurrence of the operational event. The beam current developed by the reference control signal is measured and an adjustment voltage is generated. A comparator receives the adjustment voltage and a reference voltage and provides a control voltage. A switch connects the test line generator and the control voltage to the adjustment circuit a preselected time after the occurrence of the operational event. A memory device stores the control voltage until the next occurrence of the operational event.