Digital to Analog Converter ( DAC)

make we feel what the computer result, use DAC, to convert digital result data from computer / microcontroller to analog signal (ie. voltage,sound,light), I choose DAC 0830 because its reliable & cheaper :

The DAC0830 is an advanced CMOS/Si-Cr 8-bit multiplying
DAC designed to interface directly with the 8080, 8048,
8085, Z80®, and other popular microprocessors. A deposited
silicon-chromium R-2R resistor ladder network divides the
reference current and provides the circuit with excellent temperature
tracking characteristics (0.05% of Full Scale Range
maximum linearity error over temperature). The circuit uses
CMOS current switches and control logic to achieve low
power consumption and low output leakage current errors.
Special circuitry provides TTL logic input voltage level compatibility.
Double buffering allows these DACs to output a voltage corresponding
to one digital word while holding the next digital
word. This permits the simultaneous updating of any number
of DACs.
The DAC0830 series are the 8-bit members of a family of
microprocessor-compatible DACs (MICRO-DAC™)


and below the sample circuit for audio controlling :