Circuit Devices

Understanding Circuit Devices

  • A circuit consists of various devices connected together in a loop.
  • The common devices found in a circuit include resistors, transformers, diodes, capacitors, inductors, and transistors.
  • An electric current passes through these devices when the circuit is closed (or complete).
  • Understanding how each device works is necessary for building, designing or troubleshooting various electronic devices and systems.

Resistors

  • Resistors are used to limit the current flow through a circuit.
  • They have a specific resistance value, measured in ohms (Ω).
  • Two types of resistors are common: fixed resistors, which have a set resistance, and variable resistors (or rheostats), which allow the resistance to be changed.

Capacitors

  • A capacitor stores energy in an electric field between two plates.
  • Capacitors can store and release electrical energy quickly, making them useful in devices like cameras and strobe lights.
  • Capacitors also block direct current (DC), but allow alternating current (AC) to pass through.

Diodes

  • A diode allows current to flow in only one direction - it possesses forward bias when it allows current to flow and reverse bias otherwise.
  • Diodes are common in power-supply circuits, converting AC to DC.
  • Light-emitting diodes (LEDs) emit light when an electric current passes through.

Transformers

  • Transformers are devices that can be used to step up (increase) or step down (decrease) alternating voltages in electrical power applications.
  • They work on the principle of magnetic induction, and only work with alternating (AC) current.

Transistors

  • A transistor is a semiconductor device that can amplify or switch electronic signals and electrical power.
  • It is a fundamental building block of modern electronic devices, including radios and computers.

Inductors

  • Inductors, also known as coils, use the properties of electromagnetism to store electrical energy in a magnetic field when electrical current passes through it.
  • They are commonly used in radio frequency (RF) tuning circuits and power supply filters to smoothen output voltages.