20x4 Alphanumeric LCD (Green)

20x4 Alphanumeric LCD (Green), Alphanumeric LCD is a type of liquid crystal display that displays letters and numbers. In a simple LCD, liquid crystal is put between transparent electrodes and alters the polarisation of light travelling through an electrical field. Polarisation filters cover the electrodes, ensuring that only one direction polarised light may enter through the screen. If the polarity of the liquid crystal changes owing to an electrical field, light cannot flow through the screen or a portion of it, and the screen appears black.