Current, Resistance, and Ohm's Law

Conventional Current

• Electrons are the charge that flows through wires

• Historically thought positive charges move

• Conventional current → imaginary flow of positive charges

  • Flows from positive terminal and into negative terminal (a)

  • Real current flows the opposite way​ (b)

Drift Velocity

• Think of water pumps

  • Bigger pumps → more water flowing

  • Skinny pipes (more resistance) → less water flowing

• Electrical circuits

  • Bigger battery voltage → more current

  • Big electrical resistance →less current​

• V = ɛmf

• I = Current​

• R = Resistance

  • Unit: V/A or ohm ​(Ω)

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Resistors

• Device that offers resistance to the flow of charges

• Copper wire has very little resistance

• Symbol used for a in a circuit diagram

  • Resistor

  • Wire​

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