PREEAMPLIFIER FOR TELEVISION CAMERA

摘要

PURPOSE:To prevent the abnormal operation of the pre-amplifier circuit and thus to secure the amplification at the normal operation time at all times by adding the circuit which controls the bias at the constant current type amplification part to prevent the circuit operation from being steady at the point of the abnormal operation and thus eliminating the abnormal operation of the pre-amplifier circuit. CONSTITUTION:In the direct-coupled pre-amplifier containing the DC negative feedback resistance to amplify the signal sent from the pickup tube of the TV camera, diode 10 and DC power source 11 are connected to the input terminal of constant current type is inverse amplifier 9 of the final step. Then the voltage of power source 11 is set higher than the input voltage of amplifier 9 when the pre- amplifier has the normal operation and lower then the input voltage at the abnormal operation time respectively. The bias voltage is lowered down to the voltage of power source 11 by diode 10 in order to maintain the operation of the preamplifier at the normal action time when the power source is supplied abnormally.