| 摘要 |
PURPOSE:To form a control circuit which is characterized by the stable motor control at a low speed rotation and easy manegement of amplification of a motor driving portion by detecting the balance and unbalance of a bridge by a voltage comparator, and obtaining a digital signal of a 0 or a 1. CONSTITUTION:The bridge is formed by the DC motor 1, resistors 4, 5, and 6, and a reference voltage generatos 2. The comparator 3 compares the potentials at (a) and (b) and sends out a digital signal of a 0 or a 1. The output thereof is converted to an analog signal by a low-pass filter formed by resistors 7 and 9 and a capacitor 8, and controls a motor driving amplifier which is connected as a Darlington circuit by transistors 10 and 11. Therefore, even though the amplification factors of the transistors are slightly changed at a low rpm, the change is absorbed into the output pulses of the comparator by the pulse width modulation, the rpm can be selected in the broad range. |
