Dc motor control using 555 timer IC
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- 2. Pusle-Width Modulation(PWM) *Pulse *Modulation-modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal. Pulse width modulation is a modulation technique used to encode a message into a pulsating signal.
- 3. Motor control is the beginning and some might even say the holy grail of robotics and mobility in general. Whether it is a servo, DC , stepper , gas or whatever engine/ motor, being able to control speed , torque , direction etc accurately gives a great advantage over just being able to turn it on and off. It is a great method of controlling the amount of power delivered to a load without dissipating any wasted power.
- 5. WORKING PRINCIPLE The 555 timer IC is wired in astable mode of operation. Using a potentiometer the duty cycle of the 555 timer can be controlled. The duty cycle of the timer IC can either be made narrow or broad. When the duty cycle of the IC is narrow the speed of the motor decreases and when the cycle is broad the speed increases. The timing capacitor C4&C1 charged and discharged through D1&D2. D3 used to protect the electronic circuit from the inductive loading of the motor. The output signal at pin 3 of the 555 is equal to the supply voltage switching the transistors fully “ON”. The change in the duty cycle is called modulation and as the change is occurring in the pulse width it is thereby called PULSE WIDTH MODULATION.
- 8. COMPONENTS LIST 1) BREAD BOARD - 80TK 2) 555 TIMER IC - 5 TK 3)IRFZ44 TRANSISTOR - 5TK 4) 2 10nf CAPACITORS -5TK 5)PRINTED CIRCUIT BOARD -80TK 6)FERRIC CHLORIDE - 80TK 7)MOTOR AND WHEEL - 200TK 8)10K POTENTIOMETER - 10TK
- 10. PCB LAYOUTS (Contd.) BOTTOM COPPER
- 12. PCB LAYOUTS(Contd.) 3D TOP VIEW
- 13. PCB LAYOUTS(Contd.) 3D BOTTOM VIEW
- 15. -The above circuit can also be used to control the speed of a fan or to dim the brightness of DC lamps or LED’s. -Output voltage signal across DC motor = square wave at 10Hz frequency with peak voltage at around 8- 9 Volts and rated speed of 2400rpm. -output will be noticeable to the naked eye when the motor is replaced by an LED.