Difference between Analog and Digital Circuits

Differences Circuit Electronics & Electrical

Both analog and digital circuits are extensively used in various fields of electrical and electronics engineering for signal processing. Go through this article to find out how analog and digital circuits function and how they differ from each other.

What is an Analog Circuit?

An analog circuit is a type electronic circuit that can process any analog signal or data and produce an output in analog form. Analog circuits are composed of resistors, inductors and capacitors, etc.

The type of signal which is a continuous function of time is known as an analog signal. All the real-world signals are the analog signals, therefore, the analog circuit do not require any conversion of the input signal i.e. the analog input signal can be directly fed to the analog circuit without any loss and it can be directly processed by the given analog circuit. Also, the output signal produced by the analog circuit is an analog signal.

Based on the circuit behavior and the components used, the analog circuit can be of two types viz.: active circuit and passive circuit. Amplifiers are the examples of active analog circuit while low pass filter is an example of passive circuit. The main drawback of the analog circuits is that the analog signals are very susceptible to the noise which may cause distortion of the signal waveform and causing the loss of information.

What is a Digital Circuit?

A digital circuit is an electronic circuit that processes digital signals. A signal that is a discrete function of time are known as digital signals.

The basic building blocks of digital circuits are digital logic gates. The digital circuit can process only digital signals, but the real-world signals are of analog nature. Therefore, they need to be converted into digital signals using special electronic circuit known as ADC (Analog to Digital Converter). The output of the digital circuits is also digital signals, which is required to be converted back into the analog signal.

There may be loss of information in the digital circuit during sampling process. The digital circuits can only be active circuits which means they require an additional power source to power the circuit.

Difference between Analog Circuit and Digital Circuit

The following table highlight the major differences between analog circuits and digital circuits −

Parameter	Analog Circuit	Digital Circuit
Definition	The electronic circuit which can process only analog signals is known as analog circuit.	The circuit which has ability to process only digital signals is known as digital circuit.
Input signal	The input signal to the analog circuit must be a continuous time signal or analog signal.	The input to the digital circuit is a discrete time signals or digital signal.
Output signal	Analog circuits produces output in the form of analog signals.	The output of the digital circuit is a digital signal.
Circuit components	The circuit components of the analog circuits are resistors, inductors, capacitors, etc.	The main circuit components of the digital circuits are logic gates.
Need of converters	The analog circuits can process the analog signals directly which present in the nature. Therefore, analog circuits do not require signal converters.	As the real world signals are analog, but the digital circuits can process signals only in digital form. Thus, digital circuits require signal converter, i.e. Analog to Digital Converter (ADC) and Digital to Analog Converter (DAC).
Susceptibility to noise	The analog signals are more susceptible to noise.	Digital signals are immune to the noise.
Design	The analog circuits are complex to design because their circuit components need to be placed manually.	The designing of complicated digital circuits is relatively easier by using multiple software.
Flexibility	The implementation of analog circuit is not flexible.	The digital circuits offer more flexible implementation process.
Types	Analog circuits can be of two viz.: active circuit and passive circuit.	The digital circuits are of only one type named active circuit.
Processing speed	The processing speed of analog circuits is relatively low.	The digital circuits have higher processing speed than analog circuits.
Power consumption	The analog circuits consume more power.	The power consumed by the digital circuits is relatively less.
Accuracy & precision	The analog circuits are less accurate and precise.	The digital circuits are comparatively more accurate and precise.
Observational errors	In case of analog circuits, there may be an observational error in the output.	The digital circuits are free from observational errors in the output.
Signal transmission	In case of analog circuits, the signals are transmitted in the form of waves either wirelessly or with wires.	In the digital circuits, the signals can only be transmitted through wires in the digital form.
Form of information storage	The analog circuits store the information in the form of waves.	Digital circuits store the information in binary form.
Logical operations	The analog circuit are not able to perform the logical operations efficiently.	Digital circuit performs logical operations efficiently.

Conclusion

Analog and digital circuits are the two main types of electronic circuits. The key difference between analog and digital circuits is that an analog circuit can process only analog signals, while a digital circuit can process digital signals.