The Heart of the Digital Analog Converter

An analog to digital converter (abbreviated A/D, ADC or A to D) is an electronic circuit that converts continuous signals to discrete digital numbers. The reverse operation is performed by a digital to analog converter (DAC) Typically, an ADC is an electronic device that converts an input analog voltage to a digital number. The digital output may be using different coding schemes, such as binary and two's binary. However, some non-electronic or only partially electronic devices, such as rotary encoders can also be considered ADCs.

An example of an analog to digital converter is part number DAC729KH manufactured by Texas Instruments.

DACs are now widely used in COMPACT DISC (q.v.; CD) players, in digital audio- and videotape players, and in digital signal processing audio and video equipment. Most DACs use some form of resistor network. Digital data is applied to the resistors in groups of bits. The resistances vary in definite ratios; the current flow in each one relates directly to the binary value of the bit received.