Ohm's Law Explained by Paul of theengineeringmindset.com

Introduction

• Hosted by Paul from theengineeringmindset.com
• Focus: Understanding Ohm's Law, its application, and knowledge test with two problems at the end.

What is Ohm's Law?

• Relationship between voltage, current, and resistance
• Developed by German physicist Georg Ohm
• Used to understand the behavior of electrical circuits

Ohm's Law Formulas

• Three main formulas:
  • Voltage (V) = Current (I) x Resistance (R)
  • Current (I) = Voltage (V) / Resistance (R)
  • Resistance (R) = Voltage (V) / Current (I)
• Remember using "Ohm's Triangle": V at the top, I and R at the bottom
• How to use the triangle:
  • Cover the letter you need, e.g., covering V leaves I x R

Why is Current Represented by 'I'?

• Stands for "intensité du courant" from French physicist Andre Ampere's work
• Became a standard notation

Notation Differences: V and E

• V = Voltage
• E stands for EMF (Electromotive Force)
• Can substitute V for E in formulas

Using Ohm's Triangle

• To find Voltage (V): Cover V -> V = I x R
• To find Current (I): Cover I -> I = V / R
• To find Resistance (R): Cover R -> R = V / I

Example Calculations

• Finding Voltage:
  • Circuit with a 3 Ohm resistor and 2 Amp current
  • Using formula: V = I x R -> V = 2 Amps x 3 Ohms = 6 Volts
  • Battery = 6 Volts
• Doubling Voltage Effects:
  • Doubling voltage (e.g., from 6V to 12V) doubles the current
  • Demonstrates current is directly proportional to voltage

Finding Current Example

• Circuit with a 3 Amp lamp on a 6 Volt supply
• Using formula: I = V / R -> I = 6 Volts / 3 Ohms = 2 Amps
• Doubling resistance halves current, verifying inverse proportionality

Finding Resistance Example

• Circuit with a resistive lamp on a 12 Volt supply, 0.5 Amp current
• Using formula: R = V / I -> R = 12 Volts / 0.5 Amps = 24 Ohms

Practical Applications

• Understanding opposition to electron flow in resistors
• Importance of resistors in protecting circuit components like LEDs

Additional Resources

• Free PDF guide and calculator available
• Links provided in video description
• Recommend getting a multi-meter

Problems to Test Knowledge

1. 240 Ohm lamp plugged into 120V outlet in the US: find the current.
2. Same 240 Ohm lamp plugged into UK outlet, current is 0.958 Amps: find the voltage.

Conclusion

• Further learning resources available on theengineeringmindset.com and social media.