| 摘要 |
<p>A motor control circuit includes a chopper circuit (11) including a main switching element (14) which is connected in series with the motor armature (12). The chopper is controlled by a Schmitt bistable circuit (34) which operates to switch the main switching element on when the actual motor current falls more than a set amount below a demanded level and off when the actual motor current rises more than a set amount above the demanded level, the demand level is determined by the driver"s pedal controlled potentiometers (37, 38) but is required to be modified in accordance with the motor speed. Instead of using a mechanical speed transducer, the present invention includes a circuit (40) which is connected to the output of the bistable circuit (34) and produces a signal varying in accordance with the ratio of the on and off times of the main switching element. </p> |
