Electric Circuits Notes

9.2 Electric Circuit

  • Electric circuits are closed-loop paths forming a network of electrical components, allowing electron flow.

  • These paths use electrical wires powered by a source, such as a battery.

  • The starting point of electron flow is the source, and the exit point is the return.

Simple Circuit

  • A simple circuit includes a power source, conductors, a switch, and a load.

  • Cell: the power source.

  • Load: also called the resistor, exemplified by a light bulb that illuminates when the circuit is on.

  • Conductors: typically copper wires without insulation.

    • One end connects the load to the power source, and the other connects the power source back to the load.

  • Switch: a small gap in the circuit used to open or close it; various types exist.

Advantages of Circuit Diagrams

  • Easier to draw compared to pictures.

  • Components have standard symbols.

  • Wires are represented by straight lines, simplifying interpretation.

Types of Circuits

  • Series Circuit: A circuit where the same current flows through all components; current has only one path. (only 1 loop)

  • Parallel Circuit: A circuit where the electric current has multiple paths to flow through. (has multiple loops)

Series Circuits vs. Parallel Circuits

Series

  1. The same amount of current flows through all components.

  2. Components are arranged in a line.

  3. If one component fails, the entire circuit breaks down.

Parallel

  1. The current through each component combines to form the total current from the source.

  2. Components are arranged parallel to each other.

  3. If one component fails, the others continue to function independently.

9.3 Measuring the Flow of Current

  • Diagrams of different circuit elements:

    • Battery

    • Switch

    • Buzzer

    • Ammeter

Ammeter

  • An ammeter is a measuring instrument used to measure the current in a circuit.

  • Electric currents are measured in amperes (A).

  • AA represents the ammeter in circuit diagrams.

  • The faster electrons move, the higher the current.

  • The slower electrons move, the lower the current.

  • Ammeters have two terminals: red (positive) and black (negative).

  • The red terminal of the ammeter must be connected to the positive terminal of the power supply, either directly or through other components.

  • Both ends of the ammeter are the same in a circuit diagram.

9.5 Adding or Removing Components

  • In a series circuit, the same amount of current flows through all components.

  • In parallel circuits, components are placed in parallel, splitting the current flow.

Current in Series and Parallel Circuits

  • The current in a series circuit is the same at each component.

  • An ammeter placed at any point in a series circuit will give the same reading.

  • Total current in a parallel circuit is the sum of the individual branch currents.

Adding or Removing Cells

  • Adding more cells (or using a battery with higher voltage) to a complete circuit will:

    • Make a bulb brighter.

    • Make a motor spin faster.

    • Make a buzzer sound louder.

  • More cells mean more chemical energy, which translates to more electrical energy.

Adding or Removing Lamps

  • MORE LAMPS --- CURRENT DECREASES --- LAMP GET DIMMER