AUTOMATIC BRIGHTNESS AND VOLUME CONTROL CIRCUIT FOR TV

摘要

The circuit turns the brightness to low level and provides maximum sound when air raid signals are detected. A brightness controller (Na) is connected to a switching circuit (E) and a volume controller is connected to a diode (D4) and a variable registor (VR5). An output of an audio detector (Ma) is applied to a comparator through modulator (A) and is compared with output of oscillator (C). The compared signal is transmitted to an OP amp (OP1) having feedback loop through a diode (D2) and a registor (R10). An output of the OP amp (OP1) is applied to a transistor (Q3) for controlling the switching circuit and audio control circuit.