Electronic Circuit

What is Circuit

A combination of passages, components and devices that form a working set of logic for a particular application.

A circuit is a path between two or more points along which an electrical current can be carried.

What is an Electronic Circuit

An electric circuit having at least one component that manipulates the voltage or current in the circuit.

An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, and at least one voltage or current source connected by conductive wires or traces through which electric current can flow.

Figure 1 Electronic Circuit

The circuit shown in Figure 1 is a simple electronic circuit, which consist of a voltage source, a resistor, light emitting diode and wire for connecting all these components.

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An electronic circuit can usually be categorized as an analog circuit, a digital circuit, or a mixed-signal circuit (a combination of analog circuits and digital circuits).

Analog Circuits

Analog electronic circuits are those in which current or voltage may vary continuously with time to correspond to the information being represented.

Analog circuitry is constructed from two fundamental building blocks: series and parallel circuits.

Series circuit

The same current passes through a series of components but the voltage divides across each component according to resistance.

Parallel circuit

                      
All the components are connected to the same voltage, and the current divides between the various components according to their resistance.

Basic Components

The basic components of analog circuits are wires, resistors, capacitors, inductors, diodes, and transistors.

Representation

                         
Analog circuits are very commonly represented in schematic diagrams, in which wires are shown as lines, and each component has a unique symbol.

Digital Circuit

In digital electronic circuits, electric signals take on discrete values, to represent logical and numeric values. These values represent the information that is being processed

Basic Components

                            
Digital circuits make extensive use of transistors, interconnected to create logic gates. Transistors interconnected so as to provide positive feedback are used as latches and flip flops.

Mixed Signal Circuit

Mixed-signal or hybrid circuits contain elements of both analog and digital circuits.

Examples

                
Comparators, timers, phase-locked loops, analog-to-digital converters, and digital-to-analog converters.

Most modern radio and communications circuitry uses mixed signal circuits.

For example

                  
In a receiver, analog circuitry is used to amplify and frequency-convert signals so that they reach a suitable state to be converted into digital values, after which further signal processing can be performed in the digital domain.