Analog and digital circuits

Una lettura in inglese su elettronica analogica ed elettronica digitale.


An anolog circuit is an electronic is an electronic circuit that operates with variable currents and no suddeen transitions between levels. An analogue quantity is commonly represented by a sine-wave which varies smoothly and constantly.

A digital circuit operate only with currents or voltages on two levels ignoring transmissions between them. These defined levels or states can be called: 0 and 1, low and high or on and off.

An analog circuit is better than digital ones to represent variable physical quantities in the real world but digital circuits are preferred considering that their output can be easily manipulated by computers. Moreover digital signals are less subject to errors or interference noises and can be also stored without huge problems.

We must use special converters to make digital and analogue circuits compatible. In particular there are (ADC) analogue-to-digital or (DAC) digital-to-analogue depending on the direction of the information we want to convert.

An example of converter is the modem that converts digital signals by computers and terminals into analogue signals. Another example can be the digital sound recording that is audio signals tranformed into digital data and saved on a magnetic or optical disk. These digital data must be changed back into analogue sound to be heard in a stereo-sound system.