Analog and Digital Instruments - What they Are? (Comparison and Advantages of Digital Instruments over Analog Instruments)

Analog and Digital Instruments

What are Analog Instruments?

The signals which continuously vary and take infinite values for a given range are called analog signals and the instrument that displays analog signals is known as analog instruments. In analog instruments, the signals or functions vary continuously.

Examples of analog instruments are DC potentiometer, PMMC ammeter, PMMC voltmeter, DC ammeter, DC voltmeter, whetstone meter bridge, etc.

What are Digital Instruments?

The signals which vary in discrete steps and take a finite different value in the given range are called digital signals and the instrument that displays digital signals is called a digital instrument.

Examples of digital instruments are microprocessor-based instruments, logical analyzers, signature analyzers, computers, digital counters, etc.

Comparison Between Analog and Digital Instruments (Analog Instruments Vs Digital Instruments)

Comparison between analog and digital instruments are discussed in the below table.

Parameter	Analog Instrument	Digital Instrument
Principle	The analog instruments display analog signals.	The digital instruments display digital signals.
Accuracy	Less compared to digital instruments.	More compared to analog instruments.
Resolution	Less compared to digital instruments. They can be made with a resolution of a one-part in several hundred.	More compared to analog instruments. They can be made with a resolution of one part of several thousand.
Observational errors	Analog instruments have considerable observational errors.	Digital instruments are completely free of observational errors.
Power required	More power is required compared to analog instruments.	Very negligible power required.
Portability	The analog instruments are portable. They can be moved easily from one location to another location.	The digital instruments are not portable. However, the modern development of digital instruments is extremely portable and cheap.
Cost	Analog instruments are cheap.	Digital instruments are expensive.
Examples	DC ammeter, DC voltmeter, DC potentiometer, PMMC ammeter, PMMC voltmeter, etc.	Microprocessor-based instruments, logical analyzers, signature analyzers, computers, digital counters, etc.

Analog Voltmeter Vs Digital Voltmeter

Advantages of Digital Instruments Over Analog Instruments

Some of the advantages of digital instruments over analog instruments are given below.

• The output of the digital instruments is in digital form. Therefore, the output can be given to computers, printers, counters, floppy disks, etc.
• The readings are indicated in decimal numbers. Thus, errors of reading on scale i.e., observational errors can be minimized.
• The power required to operate digital instruments is small as compared to analog instruments.
• The readings of the digital instruments can be carried up to one number of significant digits by placing the decimal numbers. Hence, accuracy can be increased.

The resolution of the digital instruments is more compared to the analog instruments as the number of bits is more in the digital instruments. The main disadvantages of digital instruments are that they are expensive and complex. So, analog instruments are still used as they are cheap and simple.