Power Dissipation Calculator
Calculate power dissipated by resistors in series and parallel circuits using Ohm's law
Calculate Power Dissipation
Voltage supplied by the source (battery, power supply, etc.)
Choose how the resistors are connected in the circuit
Circuit Analysis Results
Circuit Properties
Connection: Series
Supply Voltage: 0.000 V
Equivalent Resistance: 0.000 Ω
Total Current: 0.000 A
Power Analysis
Total Power Dissipated: 0.000 W
Total Power Supplied: 0.000 W
Heat Generated: 0.000 J/s
Active Resistors: 0
Formulas Used
Series Connection: R_eq = R₁ + R₂ + ... + Rₙ
Current: I = V / R_eq (same through all resistors)
Power: P = I² × R (for each resistor)
Power Analysis
Example Calculation
Series Circuit Example
Circuit: 12V battery with three resistors in series
Resistors: R₁ = 2Ω, R₂ = 6Ω, R₃ = 1Ω
Application: LED circuit with current limiting resistors
Calculation Steps
1. R_total = 2 + 6 + 1 = 9 Ω
2. I_total = V/R = 12V/9Ω = 1.33 A
3. P₁ = I²R₁ = (1.33)² × 2 = 3.56 W
4. P₂ = I²R₂ = (1.33)² × 6 = 10.67 W
5. P₃ = I²R₃ = (1.33)² × 1 = 1.78 W
Total Power = 3.56 + 10.67 + 1.78 = 16.0 W
Power Dissipation Formulas
Basic Power Laws
P = V × I
P = I² × R
P = V² / R
Series Circuits
• Same current through all resistors
• R_total = R₁ + R₂ + ... + Rₙ
• P_resistor = I² × R_resistor
Parallel Circuits
• Same voltage across all resistors
• 1/R_total = 1/R₁ + 1/R₂ + ... + 1/Rₙ
• P_resistor = V² / R_resistor
Power Ratings Guide
Understanding Power Dissipation
What is Power Dissipation?
Power dissipation is the process by which electrical energy is converted into heat energy when current flows through a resistor. This occurs due to the collision of charge carriers (electrons) with atoms in the resistor material, converting kinetic energy into thermal energy.
Joule's Law of Heating
- •Heat generated is proportional to I²Rt
- •Power dissipation = Energy loss per unit time
- •All dissipated power converts to heat
- •Heat must be managed to prevent component damage
Circuit Analysis
Series Circuits:
• Current is constant: I = V/R_total
• Power ∝ Resistance (P = I²R)
• Largest resistor dissipates most power
Parallel Circuits:
• Voltage is constant: V across each resistor
• Power ∝ 1/Resistance (P = V²/R)
• Smallest resistor dissipates most power
Design Considerations
- •Power rating must exceed calculated dissipation
- •Provide adequate heat sinking
- •Consider derating factors for temperature
Real-World Applications
🔥 Electric Heaters
Intentional power dissipation for heating elements, space heaters, and water heaters using resistive heating.
💡 LED Circuits
Current limiting resistors dissipate excess power to protect LEDs from overcurrent damage.
🔋 Power Supplies
Linear regulators dissipate power to maintain constant output voltage, requiring heat management.