The motor-driven actuator is used for the electrical locking, unlocking or shutting function of the closing and flap systems in automotive and industrial applications. There is an electric motor installed in the two laser-welded polyamide housing halves. As a result of the electric motor being supplied with current via pin 1 and pin 2, it moves a spindle gear, which causes the tappet to retract or extend depending on the direction of rotation. The current supply with plus at pin 1 and minus at pin 2 causes the tappet to extend. The current supply with minus at pin 1 and plus at pin 2, causes the plunger to retract. The stability of the retracted/ extended locking positions is achieved by the short-circuited motor following successful actuation. A PolySwitch (PTC) integrated in the motor provides thermal overload protection. In addition, it is possible to equip the actuators with an automatic return function (retracting or extending) by way of a mainspring.