| 摘要 |
PURPOSE:To improve safety and to increase the life of a battery by forcibly stopping the discharge of the battery when a switch element is not repetitively turned ON and OFF when the battery voltage drops. CONSTITUTION:A commercial power source (e) is rectified by a rectifier Re to charge a battery B, it is converted into a pulse signal by a transistor Q1 and the signal is supplied to a lamp L. The ON and OFF of the transistor Q1 is converted to a triangular wave by the output of an astable multivibrator formed of inverters I1-I3 and a capacitor C4, which wave is compared with a lamp voltage, and duty is so determined that the lamp voltage resultantly becomes constant. When it does not arrive at a predetermined value even if the battery voltage drops and the transistor Q1 is fully conducted, flip-flops FF1, FF2 are not reset, and the outputs of the flip-flops are held 'H' by the output of the inverter I3. Thus, the transistors Q1, Q2 are turned OFF, and the battery B is disconnected from the lamp L. |
