Overview
This lecture covers the power formula in electrical circuits, explaining key concepts and how to calculate power using voltage and current.
Power in Electrical Circuits
- Power measures the rate at which energy is used or transferred in a circuit.
- The standard unit for power is the watt (W).
- Power is calculated as the product of voltage (V) and current (I).
Power Formula
- The basic power formula is ( P = VI ), where P is power, V is voltage, and I is current.
- If voltage and resistance (R) are known, power can be calculated as ( P = V^2/R ).
- If current and resistance are known, power can be calculated as ( P = I^2R ).
Application of the Power Formula
- Use ( P = VI ) when both voltage and current are provided.
- Use ( P = V^2/R ) when voltage and resistance are provided.
- Use ( P = I^2R ) when current and resistance are provided.
- Choose the formula that matches the available information in a problem.
Key Terms & Definitions
- Power (P) — the rate at which electrical energy is transferred by a circuit, measured in watts (W).
- Voltage (V) — the electrical potential difference, measured in volts (V).
- Current (I) — the flow of electric charge, measured in amperes (A).
- Resistance (R) — the opposition to current flow, measured in ohms (Ω).
Action Items / Next Steps
- Practice calculating power using all three formulas with different given values.
- Review Ohm’s Law to understand the relationships between V, I, and R.