Definition: Analog computer is that computer, which is use to process continuously varying data. Everything we see and hear is change continuously. This changeable continuous stream of data is called analog data. Analog computer can be used in scientific and industrial applications such as measure the electrical current, frequency and resistance of capacitor, etc.
Analog computer that performs arithmetical operation by measurable quantities, such as mechanical movement, the rotation of gears rather than by number. In Analog computers, data is transmitted for its operation in the form of continuous signals, while in digital computers in the form discrete signals (or discontinuous signal).
Examples of analog computer are temperature, pressure, telephone lines, Speedometer, resistance of capacitor, frequency of signal and voltage etc.
The word analog is derived from the Greek ana-logon, meaning "according to a ratio." Analog computer use Analog signal that can be represented as a sine wave or continuous wave and that contains time-varying quantities. An analog signal may vary in signal amplitude or frequency. The analog wave's amplitude value is the measure of a wave's intensity, related to the highest point (called a crest) and lower points of the wave's, while the frequency (time) value is physical length from left to right. Examples of Analog signal are sound or human speech, over an electrified copper wire.
Both of analog and digital computer have their own uses and misuses. Their differences will be discussed in detail below.
• The basic difference between analog and digital computers is that how they process the data, analog computers are used for situation where data not to be transformed into digits. Digital computer are electronic based rather than continuous and use binary number data i.e. in the form of 0 and 1. Input can be performed in personal computer in form of letters, numbers and with binary coded languages.
• Digital computer shows result in form of monitor or other output devices while analog computer shows results in the form of voltage signals.
• Digital computer uses electronic circuits. While analog computer use resistor for flow of continuous signal.
• Analog computer cannot be produced repeated result with exact equivalence, which means analog computers are less accurate as compared to digital computers.
• Analog computers are used where exact values are not always required such as temperature and speed. While Digital computers are used where exact values required.
• As comparing with speed, analog computers are slower and less reliable whereas Digital computers are faster.