| 摘要 |
PURPOSE:To maintain the voltage applied to a DC motor substantially constant even if a battery voltage is varied by connecting a transistor in which the voltate dividing output of a voltage divider for dividing the battery voltage is as the base input in parallel with the base circuit of a drive transistor. CONSTITUTION:When an alarm switch S is closed at the set time so that an alarm output is generated from a terminal (a), transistors FT, T1 become ON, and a DC motor M is driven. When the battery E is new and a voltage higher than 1.2V is applied to a DC motor M, this voltage is applied to a diode D and between the base and the emitter of a transistor T2. Thus, the transistor T2 becomes ON, and the bias current flowed from the transistor FT to the transistor T1 is bypassed. Therefore, the applied voltage of the motor M decreases, and stabilized at 1.2V. |
