The switch block really has three roles in this screwdriver:
- In the center position it prevents electricity from flowing to the motor.
- It can supply power of either polarity to the motor, so the motor can spin in either a forward or reverse direction.
- On the bottom of the switch are the recharging contacts, so the switch block also provides recharging power to the battery.
The contacts for the motor sit in a gap in the middle of the switch contacts. With the switch in its neutral position nothing touches the motor contacts. In this picture the locations of the motor contacts are shown with green squares:
When the user presses on one side of the switch, current can flow from the battery to the motor contacts. Current flow in this picture is shown by red arrows: