| 摘要 |
1,125,724. Automatic speed control. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. Oct.19, 1965 [Oct. 22, 1964], No.44213/65. Heading G3R. [Also in Division H2] The speed of a battery-fed motor 1 is regulated by a comparator circuit comprising bridge 4-7, a reference voltage being developed across diode 7, whilst the voltage at the junction of resistors 4, 5 varies with the motor voltage. The error voltage is applied to the base-emitter of n-p-n transistor 8 whose collector is directly connected to the base of p-n-p transistor 3 which is in series with the motor. Resistor 9 compensates for variations in the motor-load. A resistor, having a negative temperature co-efficient and associated with resistor 5, may provide temperature compensation. Alternatively, the diode 7 may be arranged to provide stabilisation against temperature variations. In another arrangement, the transistors 3 and 8 are of the n-p-n and p-n-p types respectively. A lamp in parallel with transistor 3 indicates the charge condition of the battery. |
