An analog computers, works by measuring voltages and currents rather
than by the process of counting. An analog computers works on supply of
continuous electrical signals and display outputs continuously. Side
rule is an example analog device in which numbered as expressed as
distances. Another example of analog computers is a speedometer of an
automobile which continuously displays outputs in the form of speed of
the vehicle as it receives continuous signals. On the other hand
milometer (displaying distance covered by the vehicle) is a digital
device. Thus, an analog computer works by establishing analogy between
two quantities one of which is essentially continuous like electrical
signals or electrical pulses. The machine has a very limited memory and
can perform only a certain types of calculations, which makes it
specialized machine suitable for engineering and scientific
calculations. An analog computer is basically a device for solving
ordinary differential equations and can be used in solution of those
problem which can be converted to a differential equation. The accuracy
of these machines are low although these are faster in speed as compared
to digital machines because all the tasks performed in this machine are
in parallel.
Thus, we conclude an analog computer is a
special purpose computer capable of solving any physical operation
which can be represented as an ordinary differential equation. This
computer is faster than a digital computer but can give an accuracy of
not more than 99%.
Since analog computer is a special purpose device, so most of the computer are digital.In fact the word COMPUTER has become synonym of a digital computer.
