Components in Electronic Systems
Passive Components
Passive Electronic Components
Components that do not control or amplify electrical signals, but instead store, resist, or transfer energy, such as resistors, capacitors, and inductors.
- Passive components do not require an external power source to operate.
- They respond to electrical signals but do not amplify or generate them.
Fixed and Variable Resistors
Resistor
An electronic component that limits or controls the flow of electric current in a circuit.
Fixed Resistors
- Have a constant resistance value.
- Purpose: Control current flow, divide voltage, and protect components.
Variable Resistors
- Allow resistance to be adjusted.
- Types: Potentiometers and rheostats.
- Purpose: Used in volume controls, dimmer switches, and tuning circuits.
Capacitors
Capacitor
An electronic component that stores and releases electrical energy by holding an electric charge between two conductive plates.
- Energy Storage: Smooth out voltage fluctuations.
- Filtering: Remove noise from signals.
- Timing: Control the timing of circuits (e.g., in oscillators).
- Think of a capacitor as a water tank in a plumbing system.
- It stores water (energy) and releases it when needed to maintain a steady flow.
Switches
Switch
An electrical component that is used to connect or disconnect the flow of electricity in a circuit, allowing control over whether the circuit is on or off.
- Types:
- Manual: Toggle, push-button.
- Automatic: Limit switches, reed switches.
- Purpose: Turn devices on or off, change circuit paths.
Relays
Relay
An electronic switch that is activated by a current or signal to open or close another circuit, allowing a low-power signal to control a high-power circuit.
- Isolation: Separate low-voltage control circuits from high-voltage loads.
- Automation: Control multiple circuits with a single signal.
In a car, relays are used to control headlights, allowing a low-current switch to activate high-current lights.
Active Components
Active Electronic Components
Components that control the flow of electricity and can amplify signals or switch currents, such as transistors and diodes.
Diodes
Diode
An electronic component that allows current to flow in only one direction, acting like a one-way valve in a circuit.
- Rectification: Convert AC to DC.
- Protection: Prevent reverse current that could damage components.
- A common misconception is that diodes block all reverse current.
- In reality, they have a small reverse leakage current, which is usually negligible.
Transistors
Transistor
A semiconductor device with three connections that can regulate current or voltage and is commonly used for switching or amplifying signals in electronic circuits.
- Types:
- Bipolar Junction Transistors (BJTs): Use current to control current.
- Field-Effect Transistors (FETs): Use voltage to control current.
- Purpose:
- Amplification: Increase signal strength.
- Switching: Turn circuits on or off in digital devices.
