While working with Arduino, and Raspberry Pi we often face components which work in the analog principle. For example an LDR or a thermistor or laser TOF sensor operates as analogue electrical circuits.
Analog electronics is the part of electronics that exploits signals that can operate or be measured by continuous values. Analog electronics are complementary to digital electronics, which process signals with discrete values, and for which original analog signals can be integrated by analog-to-digital conversion, sampling and quantization.
Analog electronics process a signal whose value is most often measured by a physical quantity. For example, an audio amplifier processes the sound signal in a way — approximately — proportional to the electronic signal of a sound source, especially when it is reproduced on a loudspeaker. Historically, the analog mode has been the first mode exploited since the beginnings of applied electronics.
In many areas of technology, analogue technology has largely been replaced by digital technology, but some components usually remain analogue – for example, the electronics for processing the microphone and loudspeaker signals as well as the transmitting and receiving part of today’s mobile phone, which is fully digital, work still analog. In such cases, where analog and digital electronics complement or mix each other, they are also referred to as hybrid electronics or mixed-signal electronics or circuits.
Typical components of analog technology are amplifiers, filters, rectifiers, mixers, etc. In contrast to this are components of digital technology, such as logic gates, microprocessors and data storage devices.
Since humans can only process sounds and images in analogue form, but digital technology causes less interference in storage and transmission over long distances, both technologies are now combined. The signals of both technologies can be converted into each other with analog-to-digital converters or digital-to-analog converters.
One of the advantages of analogue technology is that it can be implemented with the simplest and often very few electronic components, such as resistors, coils and capacitors. A disadvantageous effect is the susceptibility to interference and the distortions of the signals, which occur on the one hand due to internal physical properties of the components and cables, and on the other hand due to capacitive and/or inductive coupling between different components.
Due to the high integrability of the components (more components and functions per area) and the sometimes lower energy consumption, digital technology is taking on more and more tasks and is increasingly displacing analog technology. However, analog and mixed circuits continue to be used for special industrial applications, such as the automotive or aerospace industries; however, they are usually reduced in size and converted into integrated circuits.
A 74HC4051 multiplexer breakout is corrected with eight LDRs (analog)
Limitations and Disadvantages of Analog Circuit
Two factors limit the accuracy with which the analog signal is processed: background noise and bandwidth.
A series of physical phenomena and interference produced by the environment, generate background noise. Analog electronics strive to maintain as high as possible, the ratio between the level of the useful signal and the average level of background noise, called simply the signal-to-noise ratio. Bandwidth limits can affect the transmission of rapid variations in the signal or its electronic characteristics.