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Electronic circuit

technology Maturity 11-13 Next article →

An electronic circuit is a specialized system used to control electricity. It consists of individual electronic components connected by conductive wires or traces. These components allow electric current to flow through the system. Common parts include resistors, transistors, capacitors, inductors, and diodes.

Simple electrical schematic with Ohms law
Simple electrical schematic with Ohms law

While electrical circuits move power, an electronic circuit must contain at least one active component. An active component is a part that can control the flow of electricity. This control allows circuits to perform complex tasks. They can amplify signals, perform mathematical computations, or move data between locations.

To understand how these systems are built, we must look at their physical structure. Early circuits used discrete components joined by individual pieces of wire. Today, most circuits use a printed circuit board, known as a PCB. A PCB is a laminated substrate with conductive traces etched onto it. Engineers use photolithographic techniques to create these precise interconnections. Once the paths are set, components are attached using solder.

PExdcr01CJC
PExdcr01CJC

Even smaller systems exist called integrated circuits, or ICs. In an IC, all components and connections are formed on a single substrate. This substrate is usually a semiconductor, such as doped silicon or gallium arsenide. The most widely used semiconductor device in these circuits is the MOSFET, or metal–oxide–semiconductor field-effect transistor.

Electronic circuits are generally categorized into three types: analog, digital, and mixed-signal. Analog circuits handle signals that vary continuously with time. In these systems, the current or voltage changes smoothly to represent information.

Common Base amplifier
Common Base amplifier

Engineers use schematic diagrams to represent these circuits. In a schematic, wires are shown as lines and components use unique symbols. To analyze these circuits, engineers apply Kirchhoff's circuit laws. These laws state that all currents at a node must equal zero. Additionally, the total voltage around any closed loop must also be zero. At very high frequencies above 1 GHz, wires are treated as transmission lines. This is known as the distributed-element model.

Digital circuits operate using a fundamentally different logic. Instead of continuous changes, digital signals take on discrete values. These values represent specific logical or numeric information. Most digital systems use binary encoding to process this data. In binary, one voltage level represents a '1' and a lower voltage represents a '0'.

Intel 8742 153056995
Intel 8742 153056995

Digital circuits rely heavily on transistors to create logic gates. These gates perform Boolean functions like AND, OR, NAND, NOR, and XOR. By interconnecting transistors to provide positive feedback, engineers create latches and flip-flops. These components allow a circuit to remain in a specific state until an external input changes it. This ability provides both logic and memory for the system.

Digital memory comes in several specific forms. One type is static random-access memory, or SRAM, which is based on flip-flops. Another common type is dynamic random-access memory, or DRAM, which stores charge in a capacitor. Because each logic gate in a digital circuit regenerates the binary signal, designers do not have to worry about distortion or gain control. This makes the design process much different from analog design. Because of this efficiency, it is possible to build extremely complex digital circuits. Modern chips can integrate billions of logic elements on a single silicon chip at a low cost.

These advanced digital circuits are found in almost all modern technology. You can find them in calculators, mobile phone handsets, and computers. Engineers use different types of chips for different purposes. Microprocessors are general-purpose computing chips used for many tasks. Some engineers design application-specific integrated circuits, or ASICs, for custom tasks. There are also field-programmable gate arrays, known as FPGAs. These are unique because their logic configuration can be modified even after they are manufactured.

Intel 8742 153056995
Intel 8742 153056995

However, as circuits get denser, engineers must manage issues like power dissipation and leakage currents.

Finally, many systems require mixed-signal or hybrid circuits. These circuits contain both analog and digital elements to bridge the gap between the two worlds. Common examples include comparators, timers, and phase-locked loops. They also include analog-to-digital and digital-to-analog converters. Mixed-signal circuits are essential for modern radio and communications. For instance, a radio receiver uses analog circuitry to amplify and convert signals. Once the signal is in a suitable state, it is converted into digital values. This allows the device to perform further signal processing in the digital domain.

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🖼️ Images & Media (4)
File:Intel 8742 153056995.jpg
Intel 8742 153056995.jpg
File:PExdcr01CJC.jpg
PExdcr01CJC.jpg
File:Common Base amplifier.png
Common Base amplifier.png
File:Simple electrical schematic with Ohms law.png
Simple electrical schematic with Ohms law.png
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