| 摘要 |
PURPOSE:To obtain a malfunction preventing circuit which reduces the power loss of a resistance connected between terminals where a noise is induced by providing a transistor (TR) which turns on only when the rectified voltage of a power source is low. CONSTITUTION:When output voltage of a rectifier 14 is lower than a specific value, a TR48 turns off, so a TR50 turns on to connect the resistance between terminals P and Q, so the voltage divided by induction impedance and resistance 46 is applied between the terminals P and Q. For the purpose, the value of the resistance 46 is so set that this divided voltage exerts no influence upon a timer circuit, thereby preventing malfunction. The time limit capacitor 22 of the timer circuit is charged without any influence of the induced noise and when it is charged up to the Zener voltage of a Zener diode 20, an SCR18 turns on to energize a relay. |
