DC motor control circuit using NE555
Are you familiar with all the applications of 555 timer circuits? If not, we can help you. We all know that for better understanding, the best source is an authenticated book on the subject. CircuitsToday presents an online store which has reviews on 3 books that are considered to be the best in providing the basics and applications of the 555 timer IC. We have reviewed them in detail. You check them out and buy them here:- 3 Great Books to Learn 555 Timer Circuits and Projects.
A simple DC motor controller circuit using NE555 is shown here. Many DC motor speed control circuits have been published here but this is the first one using NE555 timer IC. In addition to controlling the motors speed its direction of rotation can be also changed using this circuit.
A PWM circuit based on timer NE555 is the heart of this circuit. NE555 is wired as an astable multivibrator whose duty cycle can be adjusted by varying the POT R1. The output of IC1 is coupled to the base of transistor Q1 which drives the motor according to the PWM signal available at its base. Higher the duty cycle the average voltage across motor will be high which results in higher motor speed and vice versa. Change of DC motor direction is attained using the DPDT switch S1 which on application just toggles the polarity applied to the motor.
Circuit diagram of DC motor controller.
- The circuit can be assembled on a Vero board or PCB.
- Use 12V DC for powering the IC.
- Vm is the power supply for motor and its value depends on the motors voltage rating. Any way maximum Vceo for BD139 is 80V and so Vm should not be exceeded 80 volts.
- Maximum collector current BD139 can handle is 1.5A and so do not use a motor that consumes more than 1.5 amperes of current.
- A heat sink is necessary for BD139.
Few other DC motor speed control circuit you may be interested in: