Electrical Components Notes

Power Sources

  • Power sources supply electrical energy to circuits or devices, enabling operation.
    • Cells: Basic units generating electrical energy through chemical reactions, used in small devices.
    • Batteries: Multiple cells connected to provide higher stored electrical energy capacity, powering various devices.
    • Power Supply (DC): Converts alternating current (AC) from outlets to direct current (DC) for stable voltage output.

Switch

  • A switch controls current flow in a circuit, opening or closing it to turn devices on/off or select current pathways.
    • Single Pole Single Throw (SPST) Switch: One input and one output for simple on/off control.
    • Single Pole Double Throw (SPDT) Switch: One input and two outputs for switching between two circuits.
    • Double Pole Double Throw (DPDT) Switch: Two inputs and two outputs for simultaneous switching between two circuits.
    • Push to Make (N/O) Switch: Open by default, closes when pushed to complete the circuit.
    • Push to Break (N/C) Switch: Closed by default, opens when pushed to break the circuit.
    • Magnetic Reed Switch: Controlled by a magnetic field, opening or closing the circuit based on the field's presence.

Resistors

  • A resistor limits current flow in a circuit, controlling voltage levels, dividing voltage, providing circuit protection, and setting component operating conditions.
    • Fixed Value Resistor: A resistor with a specific resistance value.
    • Variable Resistor: A resistor whose resistance can be manually adjusted.
    • Potentiometer: A three-terminal resistor used to adjust voltage or control volume.
    • Light Dependent Resistor (LDR): Resistance decreases with increasing light, useful for light-sensing.
    • Thermistor (NTC): Resistance decreases with increasing temperature, useful for temperature-sensing.

Capacitors

  • A capacitor stores and releases electrical energy in an electric field, used for filtering, energy storage, timing, coupling, and voltage regulation.
    • Polarized Capacitors (Electrolytic and Tantalum): Have specific polarity and must be correctly oriented.
    • Non-Polarized Capacitors: No specific polarity, can be connected in either orientation.

Diodes

  • A diode allows current flow in one direction only, blocking it in the opposite direction; used for rectification, voltage regulation, signal demodulation, and reverse voltage protection.
    • Silicon Rectifier Diode: Used to rectify AC to DC.
    • Light Emitting Diode (LED): Emits light when current flows through it; used for indicators, displays, and lighting.

Motors

  • Motors convert electrical energy into mechanical energy for motion or rotation, used in machinery, vehicles, appliances, robotics, and industrial equipment.
    • DC Motor: Rotates when current flows through it.
    • Servo Motor: Precise control over position, speed, and acceleration; used in robotics and automation.
    • Stepper Motor: Divides rotation into equal steps for precise positioning; used in CNC machines and 3D printers.

Relays

  • A relay is an electromechanical switch using an electromagnetic coil to control contacts, used for remote/automatic control, switching high-power loads, and providing isolation.
    • Single Pole Double Throw (SPDT) Relay: Controls high-power devices with a low-power signal.
    • Double Pole Double Throw (DPDT) Relay: Controls two separate circuits.

Transistors

  • Transistors are semiconductor devices used for amplification, switching, and signal processing.
    • NPN Transistor: A bipolar junction transistor (BJT) that amplifies or switches signals.

Integrated Circuits

  • An integrated circuit is a miniaturized circuit consisting of semiconductor devices, passive components, and conductive traces on a single substrate, performing functions like amplification, signal processing, logic, memory, and control.
    • Voltage Regulator: Maintains constant output voltage.
    • L293D Motor Driver: Controls speed and direction of DC or stepper motors.
    • UNL2803 Darlington Driver: Controls higher current loads like relays and solenoids with low-power signals.
    • Microcontroller: A small computer with a processor, memory, and I/O peripherals.

Multimeters

  • Multimeters measure voltage, current, resistance, and other electrical parameters.
    • Voltmeter: Measures voltage.
    • Ohmmeter: Measures resistance.
    • Ammeter: Measures current.

Miscellaneous

  • Electromagnet: A coil of wire with an iron core magnetized when current flows.
  • Solenoid: An electromagnet moving a plunger or actuator when energized.
  • Piezo Sounder: Produces sound when current is applied.
  • Bulbs: Produces light when current passes through the filament.

Activity

  • Add the circuit symbol and a picture for each electrical component.

WACE Questions

  • Relevant WACE questions from past years:
    • 2016: Q37 and Q43a
    • 2017: Q31
    • 2018: Q31, Q32, and Q42a
    • 2019: Q31
    • 2020: Q31 and Q36
    • 2021: Q37