Understanding Voltage and Current Basics

Sep 2, 2024

Basic Electricity Lecture Notes

Overview of Current and Voltage

  • Current: Flow of electrons in a wire.
    • Measured in amps (amperes).
    • Indicates how many electrons flow past a point per second.
  • Voltage: Drives the current in an electric circuit.
    • Acts like a pushing force that moves electrons.

Demonstration with Electric Motor

  • Adjustable Power Supply:
    • Can generate various voltages for circuit design.
    • Measures current flow.
  • Motor Example:
    • At 0 volts: Motor is inactive.
    • At 1 volt: Current is ~1.8 amps, energy flows to the motor.
    • At 2 volts: Increased pushing force results in 2 amps of current, speeding up the motor.
    • Higher voltage = more current = faster motor speed.

Applications of Voltage

  • Powering Devices:
    • Used in motors, light bulbs, electronics.
  • Carrying Information:
    • Different voltages can represent binary data (0s and 1s).
    • Example: 0 volts = 0, 5 volts = 1 in communication systems.

Understanding Voltage

  • Chemical Reaction in Batteries:
    • Creates voltage; one side is more negatively charged.
    • Pushes electrons away, creating current in a complete circuit.

Definition of Voltage

  • Voltage: Difference in electrical potential energy per unit charge between two points.
    • Potential Energy: Ability to do work (e.g., moving or heating).
    • Measured in joules.

Units of Charge

  • Coulomb: Standard unit of charge.
    • 1 amp = 1 coulomb of charge flowing per second.
    • 6.24 x 10^18 electrons = 1 coulomb.

Energy Transfer in Circuits

  • Electrical Potential Energy:
    • Measured in joules.
    • Example: 1.5 volt battery = 1.5 joules per coulomb.
  • Energy Flow Example:
    • 1 volt with 1.8 amps = 1.8 joules/second through the motor.
    • 2 volts with 2 amps = 4 joules/second.

Voltage as a Relative Measurement

  • Voltage Definition: Difference in electrical potential energy between two points.
    • Example: 9 volt battery = 9 joules for every coulomb flowing.
  • Voltage is relative; often referred to as potential difference.

Conclusion

  • Voltage can also be called tension or potential difference.
  • Understanding the relationship between voltage, current, and energy is crucial for working with electricity.

Next Steps

  • Watch the next video for more information.
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