Voltage and Potential Difference

Introduction

• Presenter: Paul from TheEngineeringMindset.com
• Topics covered:
  • Definition of voltage and potential difference
  • Measuring voltage
  • Direct vs. alternating voltage
  • Global voltage variations

What is Voltage?

• Voltage is the push that moves free electrons around a circuit.
• Without voltage, electrons move randomly and are not useful.
• Analogy: Voltage is like pressure in a water pipe.
  • Full tank = high pressure; partly filled tank = low pressure.
  • Opening a valve allows water to flow according to pressure difference.

Potential Difference

• Potential difference indicates the work that can be done by a circuit.
• Example: Two lakes at the same level have no potential difference; one lake higher has the potential to flow down.
• Electrical example: Battery has a potential difference of 1.5 volts between terminals.
• Connecting a wire allows electrons to flow, doing work (e.g., lighting a lamp).

Combining Batteries

• Connecting batteries in series increases voltage (e.g., 1.5V + 1.5V = 3V).
• Connecting batteries in parallel keeps voltage the same (1.5V) but allows longer operation.

Measuring Voltage

• Voltage is measured in volts (V).
• Units of measurement:
  • Pressure in pipes can be expressed in bar, PSI, etc.
• To measure voltage, use a voltmeter in parallel with the circuit.
  • Example: Measure across a battery (1.5V) and across components like lamps.

Voltage vs. Volts

• Voltage: the pressure of the electrical potential.
• Volts: unit of measurement for voltage.
• Example: 1 volt drives 1 coulomb of electrons through 1 ohm of resistance in one second.

Direct Voltage

• Direct voltage (DC) is constant and flows in one direction (e.g., batteries).
• Represented with a capital V and a horizontal line above.
• Example: AA battery (1.5V) and 9V battery.

Alternating Voltage

• Alternating voltage (AC) alternates direction; polarity changes.
• Plotted voltage creates a sine wave graph.
• Represented with a capital V and a wave line above.

Global Voltage Variations

• Majority of the world uses 220-240V; North and Central America use 110-127V.
• Voltage varies depending on electricity demand.
• Historical reasons for voltage differences: lack of standardization and early distribution practices.

Product Compatibility

• Different devices are rated for specific voltages.
  • Example: U.S. hair dryer (110V) vs. European socket (220V).
  • Check manufacturer labels for voltage compatibility (e.g., laptops may work with multiple voltages).

Conclusion

• Encouragement to continue learning in electrical engineering.
• Reminder to follow on social media and ask questions in the comments.