The display may be liquid crystal or light emitting diode. 可以采用液晶或发光二极管显示。
When powering a light emitting diode, a comparatively large current flows through the resistor, so you need to consider the power rating of the resistor you choose. 当为发光二极管供电时，会有相对较强的电流通过电阻器，因而要考虑所选择的电阻器的额定功率。
