Hand-operated electrical screw-driver with DC motor and braking circuit

摘要

A hand-operated tool uses a DC motor and a braking circuit. The motor 1 is in parallel with a first transistor 10 which is controlled by a second one 12. A third transistor 13 carries the current during motor operation and charges up a condenser 15. The gate voltage for this transistor comes from a fourth one 19. This in turn is switched on or off by a fifth transistor 23 according to a command from the ECU 2. A sixth transistor 26 is activated by the ECU during braking, switching the first and second transistors so that the condenser discharges through the latter. The first and third transistors are FET's.