Analog Signal

An analog signal is a continuous signal and an analog signal represents the equivalent of another quantity. Basically an analog signal is a continuous electrical signal. Analog signals are used to carry information. Basically this signal is represented by a sine wave and this signal has a continuous range of values. Generally analog signals are used only in analog devices. Examples of analog signals are natural sounds, human voices, analog phones, old land line telephones, etc.

Basically instrumentation devices use 4 to 20 mA or 0 to 20 mA signals. And this instrument or controller keeps this voltage constant and takes it as current signal.

An analog signal is a form of electrical energy such as voltage, current. Analog signal is more accurate than digital signal and analog signal has infinite memory. Analog signals produce more noise and analog signals have lower bandwidth