The acquisition of data, from a transducer, so that these data can be converted to digital form and delivered directly to a computer is done through devices called ADC or Digital Analog Converters. The figure shows a very simple converter with an 8-bit definition input and output channel. This version that drives LEDs on the output can be used for teaching purposes to explain the principle of operation of the circuit. When the input voltage varies between 0 and 5 Volts the digital indication varies between 0000 0000 and 1111 1111 which corresponds to a scale from 0 to 256. We observe that the output of this circuit is fully compatible with the parallel inputs of the IBM family computers PC which allows its direct connection in practical data acquisition systems of a channel. Switch S1 (which can be replaced by a timer) enables the circuit so that we can make the controlled acquisition.
