Servo Tester and controlling Circuit

This below circuit is used to turn a servo clockwise and anti clock wise manually.By Pressing the Forward and reverse button we can control the rotation of servo motor for a short period of time.The output shaft has a disk or wheel containing holes. A linkage or push-rod is fitted to a hole and when the disk rotates, the shaft is pushed and pulled. The shaft only rotates about 180 degree to actuate flaps or ailerons etc.

Servo Tester Diagram





A port can be used to control the position of the servo by using the following circuit. It produces a positive pulse between about 0.9 milliseconds and 2.1 milliseconds. The off period between pulses is about 40 milliseconds. This can be shortened by reducing the value of the 3M3 resistor.

Servo Controller circuit diagram