We can look at electronics in two different ways, both of which have different uses, which are analog vs. digital electronics. In short, analog electronics deals with continuous, smoothly varying signals, and digital electronics is about handling discrete signals (which are either on or off or in other words, 1 or 0).
In general sense, analog means something that is comparable to / similar to something else that can continuously vary. This varying thing can be anything such as temperature, pressure, position, voltage…
So in analog electronics, the signals can be represented by varying voltage or current levels proportional to the signal.
The physical quantity is converted to analog signals by a transducer.
Analog electronics has many uses, of which we list only a few below:
It is used for signal amplification, modulation and filtering for purposes such as handling sound and audio communication. Analog systems can be used for radio communication.
Because analog signals are continuous, they can be used to precisely measure and monitor physical quantities by using sensors and transducers.
Voltage regulation and stabilization
Because analog signals are continuously, gradually varying, they can represent a lot of different values with high accuracy and resolution, with a very wide range of values.
Much more susceptible to noise and interference than digital systems, which decrease signal quality. Noise susceptibility causes data degradation or even loss, decreases data capacity of analog systems. In long distances this is pronounced even more by introduction of more noise and signals losing energy. Analog filters can be used to reduce noise and signal shaping.
During design it is more difficult to achieve noise reduction and precision.
Digital electronics deals with digital signals that either take the values on or off. We say digital because the values of on and off are represented by 1 and 0, the digits of binary numbers.
Digital circuits work with logic functions by using AND, OR, NOT logic gates and a few more. From the use of these logic gates, integrated circuits and a whole generation of our electronics devices, anything from digital watches upto supercomputers came into existence.
Digital signals are far more resistant to noise than analog signals because even if there is some noise interference, we can still easily know whether the signal is on or off ( 1 or 0). Distinguishing between different signal levels is easy.
This (1 or 0) is all that matters for us to be able to process that information, unlike analog electronics where the noise can distort the quality of signal which has a wide range of continuously varying values, some of which may be subject to degradation, get lost or change.
Noise resistance, which is the most fundamental advantage of digital electronics and dealing with discrete (1or 0) values have important positive effects:
-Making precise circuits that produce dependable signals and mass producing them is much more easier.
-Dependable, high quality signal transmission over long distances are far more easier. Even in noisy environments, digital signals can be reproduced to its original very easily.
-Data storage is easier.
-Complex operations and a wider range of tasks can more efficiently be handled with digital systems than analog.
Digital circuits require encoders and decoders, microprocessors, memory components, logic gates, flip flops, intricate coding and algorithms. This can increase costs, complexity and power consumption and make troubleshooting harder.
Digitals signals are not ideal in certain situations where analog signals fit better.
Where high resolution, continuous variations and fine details are needed, analog usually fits better due to its ability to continuously represent values. Analog systems can handle an infinite range of input values. With discrete digital values this is inherently more difficult and some information (quantity and quality) of signal may be lost which can happen during conversion of analog to digital. Some extreme values may not also be represented with digital.
When converting analog to digital signals there can also be delays . Analog systems however do not experience this, as they can represent continuously varying quantities easily. Delay is more pronounced especially during real time applications.
Digital technology progresses at a faster speed therefore obsolescence is more common.
Although the design can be simpler in some situations, making changes to digital design is more difficult. Analog systems are more flexible regarding making changes.