| 摘要 |
<p>PURPOSE:To set a hysteresis voltage and a threshold level independently by using a hysteresis voltage setting circuit independently to a bias resistor applying a bias voltage to a differential amplifier. CONSTITUTION:A hysteresis voltage setting circuit 1 supplying a current independently to at least one bias resistor corresponding to a signal level is provided. Thus, in supplying independently a constant current I0 to a bias resistor R6, the hysteresis voltage is set by the constant current I0 independently of a bias voltage Vt, and the threshold voltage is set by varying the bias voltage Vt while the hysteresis voltage is held constant by the constant current I0. Since the threshold level and the hysteresis voltage are controlled independently, the titled circuit is used in common as a luminous quantity detection circuit for a video camera of plural kinds different in characteristic such as an optical system circuit or a signal processing circuit.</p> |
