| 摘要 |
PURPOSE:To obtain the driving device in the titled for Japanese typewriters and the like wherein a current is constant regardless of load impedance, by connecting reference resistors to the emitter of a power transistor, connecting a DC solenoid to the collector, and changing the base potential in multiple stages. CONSTITUTION:In the driving circuit for the DC solenoid, the reference resistors R4-R6 are connected to the emitter of the power transistor Q2 in addition to an emitter resistor R2. The DC solenoid RL2 is connected to the collector. The base potential VB can be changed in multiple states by the switching of a rotary switch SW2. Since the collector current of the power transistor Q2 is approximately equal to the value of base potential V2/emitter resistance R2, the collector current can be kept constant by changing the base potential VB by switching the switch SW2, regardless of the impedance of the DC solenoid. |
