Esp8266 Arduino programming example PWM

PWM

This article will show you how to use ESP8266 NodeMCU Generate PWM The signal , Adjust by changing the duty cycle over time LED brightness .

ESP8266 GPIO It can be set to output 0V or 3.3V, But in 0~3.3V No voltage can be output between . For all that , Pulse width modulation can be used (PWM) Output “ false ” Medium level voltage , Thus, different levels of LED The way of brightness .

If very quickly in HIGH and LOW Switch between LED The voltage of , Eyes will not be able to keep up LED Speed of switch ; You will only see some gradients of brightness .

This is basically PWM How it works —— By generating a very high frequency in HIGH and LOW The output varies between .

The duty cycle is LED Part of the time period set to high level . The following figure illustrates PWM How it works .

50% Caused by the duty cycle of 50% Of LED brightness ,0 The duty cycle means LED Fully closed ,100 The duty cycle means LED Fully open . Changing the duty cycle is a way to produce different brightness levels .

About PWM More about , Please refer to ：

• Ard