PHOTO-ELECTRIC CONVERSION CIRCUIT

摘要

PURPOSE:To keep the output of an amplifier at a fixed level by performing the input feedback of the DC component of the output of a parallel feedback type amplifier via the 2nd amplifier. CONSTITUTION:The DC output Vout of an amplifier 30 serving as a parallel feedback type preamplifier is fed back to the input of the amplifier 30 through an amplifier 31. Then the value of a capacitor 40 is selected so that the response of the amplifier 31 is equal approximately to DC. When the Vout is lowered, the input of the amplifier 30 rises when it is fed back to the amplifier 30 via the amplifier 31. While the input of the amplifier 30 is lowered when the Vout rises.