Understanding Voltage

Introduction to Voltage

• Definition: Voltage is the force that pushes free electrons around a circuit.
• Relationship to Current: Without voltage, free electrons move randomly, resulting in no useful current.
• Analogy: Voltage can be likened to water pressure in pipes.
  • Full tank = high pressure, partially filled tank = low pressure.
  • Opening a valve allows more water to flow from higher pressure to lower pressure.

Voltage vs. Potential Difference

• Voltage is sometimes referred to as potential difference.
• Potential Difference: Indicates how much work can potentially be done by a circuit.
  • Example: Two lakes at the same level = no potential; one lake higher = potential for water to flow.

Measuring Voltage

• Unit of Measurement: Voltage is measured in volts (V).
• Measurement Method: Use a voltmeter or a multimeter to measure voltage by connecting across two points in a circuit.
• Example Measurements:
  • Single battery: 1.5V
  • Two lamps in series with a battery: 1.5V across the battery, 0.75V across each lamp.

Types of Voltage

Direct Voltage (DC)

• Definition: Constant pressure that moves electrons in one direction.
• Examples: AA battery (1.5V), 9V battery.
• Visual Representation: A straight line when plotted against time.

Alternating Voltage (AC)

• Definition: Voltage where electrons alternate direction; polarity changes.
• Visual Representation: Sine wave when plotted against time.
• Common Voltage Levels:
  • 220-240V in most countries.
  • 110-127V in parts of North/Central America.

Consequences of Voltage Levels

• Different voltages are due to historical factors and standardization efforts by governments and companies.
• Potential Issues:
  • Plugging a 110V appliance into a 220V socket can burn out the appliance.
  • A 220V appliance plugged into a 110V socket may not operate effectively.

Conclusion

• Always check appliance compatibility with voltage levels before use.
• For further learning, refer to previous videos on electrical circuits and concepts.