Right and Left Motor

Right and Left Motor

	The right and left motor is a small motor which has a small rating current.
	The rotation is changed by changing the polarity of operating power.
	The change of direction is implemented using a circuit called H-Bridge.

H-Bridge Schematic

Circuit Problems and solutions

There are many problems found in this circuit, below we stated a good solution for some of them, the problems may be as:

1- The output of the TTL Buffer is less than 5V which gives a weak current to the motor that result in slow motion.

Solution: use CMOS Buffer instead of TTL Buffer because its output is exactly 5V.

2- The maximum allowable current can be driven from the CMOS Buffer should not exceed 25mA.

Solution: select a suitable Resistance value in the base of the transistors to limit the driven current from the CMOS Buffer under its maximum value limit.

3- It is required to achieve high starting current in the beginning of the motion which may burn the components.

Solution: use a large capacitor at the load terminals that gives a sufficient voltage difference across the Motor at the start.

A serious problem:

The H-Bridge is not recommended for high loads that need a large current because the transistors are heated up and may fail, so we use the Relay as a Driver circuit for the Forward and Backward Motor.