2026-05-20 20:48

Status: #new

Tags: #physics #electromagnetism #circuits

4.3 Voltage, Current and Ohms Law

Voltage

• The volt is defined as $\frac{Joules}{Coulomb}=Volt$
• Voltage is the difference in electric potential between points of a system
• Change in energy -> heat temperature -> heat generation

Why Birds don't get electrocuted on high voltage?? *

• The bird has the same volts as the wire, where the wire acts as a ground for the bird such that the VOLTAGE is 0

Electric Current

• The flow of net charge
• Measured as $\frac{Coulomb}{second}=Ampere$

Electron Drift

• While Electrons do RANDOMLY move,
• When the circuit is closed, the electric field pushes the electrons to "drift" in a direction
  • This creates Electric Current

Electron Charge and Kinetic Energy*

$+(high)\to -(low),ke(low)\to ke(high)$
$-(low)\to t(high),ke(high)\to ke(low)$

Current vs Electron flow

• Electron Flow moves in the opposite direction of charge
  

Ohms Law

$V=IR$
$I=\frac{V}{R}$
Voltage (V) - Difference in Electron Potential (V)
Current (I) - Net flow of charge (A)
Resistance (R) - How much charge flow is impeded ($\mathrm{\Omega }$)

References

4.0 Electrical Charge
4.1 Electric Fields
4.2 Electrical Potential