The 555 Fan
1 Pulse Width Modulation (PWM)
Learn It
- The 555 timer chip creates pulses on the outputs based on how quickly the capacitor on the input charges and discharges.
- We want to control the speed of the fan, so how can we use these pulses to change how fast the motor spins.
- Below you will be introduced to the PWM concept, you only need to watch the first 2 minutes.
- Below is a video of the 555 Fan connected to an oscilloscope where you can visually see the pulse widening and narrowing.
Research It
- Conduct a little web research to find out what is meant by Pulse Width Modulation (PWM).
Badge It - Silver
- Upload your research, explaining how PWM works. You need to include images.
Badge It - Gold
- A 555 timer circuit can generate PWM, but a microcontroller (Genie chip) can do the same thing.
- We can program an output of a Genie chip to create PWM.
- Design the circuit below.
- Describe what happens when you adjust the potentiometer.
Badge It - Platinum
- Write a program that allows the user to change the speed the fan spins at by using what you have learned about PWM.
