It shows a display driving circuit digital voltmeter. Liquid crystal display (LCD) itself does not light, it is the use of external
incident light display digital devices. IC] LD130 is an input voltage detection circuit will detect an analog voltage value into four digital signals, sent by the foot digital display driver IC JC2 DF411 in. 7 segment driver IC2 output signal into three groups, by a digital sign in front of CD4030 two gates to drive.