The circuit shown in the figure makes possible to control a servomotor from a remote oscillator using a 555. In addition to integrated circuit 555, the circuit uses an NE544 which is an amplifier for servo control that already has the power steps for this type of application. Note that the servo used has a 50k ohm feedback potentiometer that determines its position. In this way, the voltage generated by the 555 which is a function of its frequency will be compared with the voltage given by the position of the feedback potentiometer thus determining its stop position. In other words, in this circuit the position of the servo depends on the frequency of the oscillator formed by the 555. The NE544 is not an easy component to obtain.
