| 摘要 |
A cosmetic appliance with a rotating brush, such as for nail treatment, has external electronic control of the motor speed, from zero to full speed, by means of a potentiometer and thyristor control circuit. The control circuit in series with the drive motor (1) consists of a thyristor (13) and two diodes (7,8) in parallel with a potential divider potentiometer (12). A series resistor (11) controls the voltage to the gate of the thyristor and the diodes ensure a firing of the thyristor even at very low motor speeds. Random voltage variations are excluded by an electrolytic capacitor (10) in parallel with the motor and another (9) between the gate of the thyristor and the cathode of the diode (8).
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