Abstract: A comparator is provided with a pair of transistors which are continuously in ON state, in which a switch unit constructed of a diode pair, for switching a current path in response to a high/low relationship between a voltage level of an input signal and a voltage level of a reference voltage, and a unit for converting a current into a voltage level are provided between emitter terminals of the transistor pair.

Abstract: A comparator is provided with a pair of transistors which are continuously in ON state, in which a switch unit constructed of a diode pair, for switching a current path in response to a high/low relationship between a voltage level of an input signal and a voltage level of a reference voltage, and a unit for converting a current into a voltage level are provided between emitter terminals of the transistor pair.

Abstract: An AFC voltage superimposing circuit for an electronic tuner using a plurality of varactors as a tuning element, comprising a plurality of resistors for superimposing an AFC voltage on a tuning voltage and a bypass circuit. The bypass circuit includes at least a voltage regulating diode and a diode which are connected in series so as to have the characteristic of permitting a current to flow in one direction only. When the tuning voltage exceeds a predetermined level, the voltage regulating diode comes into a conducting state, thereby increasing the AFC voltage variation superimposed on the tuning voltages, so that the interchannel deviation of AFC sensitivity may be gently compensated.