Which statement about Arduino UNO PWM capability is true?

• A. It has eight PWM pins
• B. It has six PWM pins
• C. It has twelve PWM pins
• D. It has four PWM pins

Answer: (B)

PWM on the Arduino UNO comes from the ATmega328P’s hardware timers. There are three timers, and each timer can drive two output pins with PWM, giving a total of six PWM-capable pins. Those pins are 3, 5, 6, 9, 10, and 11. Using analogWrite on these pins lets you set a duty cycle from 0 to 255, which controls how bright an LED is or how fast a motor runs, all without a separate digital-to-analog converter. That’s why six PWM pins is the right count for the UNO. The numbers in the other options don’t match the UNO’s hardware, though other boards with more advanced timers can have more PWM-capable pins.