Critical Electric Circuit Components to Know for AP Physics 2 (2025)

Understanding critical electric circuit components is key in AP Physics 2 (2025). These elements, like resistors, capacitors, and transistors, shape how circuits function, influencing everything from energy storage to current flow and voltage regulation in modern electronics.

1. Resistors

   • Limit the flow of electric current in a circuit, measured in ohms (Ω).
   • Follow Ohm's Law (V = IR), where V is voltage, I is current, and R is resistance.
   • Can be fixed or variable (potentiometers), affecting circuit behavior and voltage division.

2. Capacitors

   • Store and release electrical energy, measured in farads (F).
   • Charge and discharge through a dielectric material, influencing timing and filtering in circuits.
   • Used in applications like smoothing out voltage fluctuations and coupling/decoupling signals.

3. Inductors

   • Store energy in a magnetic field when current flows through them, measured in henries (H).
   • Resist changes in current, making them essential for filtering and energy storage in circuits.
   • Commonly used in transformers and in applications like radio frequency circuits.

4. Diodes

   • Allow current to flow in one direction only, acting as a one-way valve for electricity.
   • Used for rectification, converting AC to DC, and protecting circuits from reverse polarity.
   • Different types include standard, Zener (for voltage regulation), and light-emitting diodes (LEDs).

5. Transistors

   • Act as switches or amplifiers, controlling current flow in a circuit.
   • Fundamental building blocks of modern electronics, enabling complex functions in devices.
   • Can be bipolar junction transistors (BJTs) or field-effect transistors (FETs), each with unique characteristics.

6. Batteries and Power Sources

   • Provide the necessary voltage and current to power circuits, with various chemistries (alkaline, lithium, etc.).
   • Can be rechargeable or non-rechargeable, affecting their application and lifespan.
   • Essential for portable devices and backup power systems.

7. Switches

   • Control the flow of electricity by opening or closing a circuit.
   • Can be mechanical (toggle, push-button) or electronic (transistor-based).
   • Used in virtually all electronic devices to enable or disable functionality.

8. Fuses and Circuit Breakers

   • Protect circuits from overcurrent by breaking the circuit when current exceeds a safe level.
   • Fuses are one-time use, while circuit breakers can be reset after tripping.
   • Essential for preventing damage to components and ensuring safety in electrical systems.

9. Transformers

   • Transfer electrical energy between circuits through electromagnetic induction, changing voltage levels.
   • Used to step up (increase) or step down (decrease) voltage for efficient power distribution.
   • Critical in power grids and various electronic devices for voltage regulation.

10. Integrated Circuits (ICs)

    • Miniaturized electronic circuits that combine multiple components (resistors, transistors, capacitors) into a single chip.
    • Enable complex functions in a compact form, essential for modern electronics.
    • Used in everything from microcontrollers to signal processing and communication devices.