Brightness Adjustment

This is a brief guide to show how you can use a variable resistor, such as a dial or a slider potentiometer, to adjust the backlight brightness of an LCD panel that uses PWM (Pulse Width Modulation). The usual way to adjust the backlight brightness on a monitor is with +/- type buttons or as part of the on screen menu commands, however a dial or slider can be faster or more intuitive in some installations.

In simple terms this method uses a small analog to PWM adaptor board to convert the voltage from the variable resistor to a PWM signal. The PWM signal is then passed to the LCD panel backlight as usual. Here is an example diagram:

analog backlight brightness adjustment

The example is shown using an ALR-1920 but the connection is the same with any Digital View LCD controller board. For a full list of controllers see:


For more on LCD panel backlights and brightness see: