Volts Amps Watts Calculator
Calculate electrical power relationships using voltage, current, and power. Essential for electronics, electrical engineering, and understanding electrical circuits and devices.
Calculate Electrical Power
Enter any two electrical values to calculate the third:
Power (P) = Voltage (V) ร Current (I)
Voltage (V) = Power (P) รท Current (I)
Current (I) = Power (P) รท Voltage (V)
Understanding Electrical Power and Ohm's Law
Electrical power calculations are fundamental to understanding how electricity works in circuits and devices. The relationship between voltage, current, and power forms the basis of electrical engineering and electronics.
Ohm's Law and Power Relationship
โก Ohm's Law
V = I ร R
Voltage equals current times resistance
Fundamental relationship in circuits
Named after Georg Simon Ohm
Basic electrical engineering principle
๐ Power Formula
P = V ร I
Power equals voltage times current
Measures energy transfer rate
Units: Watts (W)
Essential for electrical design
๐ Complete Relationships
V = P รท I (Voltage from power and current)
I = P รท V (Current from power and voltage)
P = V ร I (Power from voltage and current)
All three formulas are equivalent
Choose based on known values
Electrical Units and Conversions
| Quantity | Symbol | Unit | Common Multiples | Description |
|---|---|---|---|---|
| Voltage | V | Volts (V) | kV, mV, ฮผV | Electrical potential difference |
| Current | I | Amperes (A) | kA, mA, ฮผA | Flow of electric charge |
| Power | P | Watts (W) | kW, MW, mW | Rate of energy transfer |
| Resistance | R | Ohms (ฮฉ) | kฮฉ, Mฮฉ, mฮฉ | Opposition to current flow |
| Energy | E | Watt-hours (Wh) | kWh, MWh | Electrical energy consumption |
Common Electrical Devices and Power Ratings
๐ก Lighting
LED Bulb: 5-15W
Incandescent: 40-100W
Fluorescent: 15-40W
Street Light: 150-400W
Power determines brightness
๐ฑ Electronics
Phone Charger: 5-18W
Laptop: 45-90W
Desktop PC: 300-500W
TV: 50-200W
Power supply ratings
๐ Appliances
Microwave: 800-1500W
Toaster: 800-1500W
Hair Dryer: 1200-1800W
Electric Kettle: 1200-2000W
Heating elements
Power Consumption Categories
๐ Very Low Power (< 1W)
Sensors, LED indicators
Clocks, calculators
Remote controls
Small electronic components
Energy harvesting devices
๐ฑ Low Power (1-100W)
Smartphones and tablets
Laptops and small monitors
LED lighting
Small kitchen appliances
Power tools
๐ Moderate Power (100-1000W)
Desktop computers
Large monitors
Kitchen appliances
Space heaters
Power tools
Electrical Safety Considerations
โก Voltage Hazards
Low voltage (<50V): Generally safe
Household (120-240V): Respect electricity
High voltage (>1000V): Extremely dangerous
Always use proper protection
Know emergency procedures
๐ Current Hazards
Small currents: Can be felt
Milliamps: Muscle contraction
Amps: Severe burns, death
Ground Fault Circuit Interrupters (GFCI)
Never work on live circuits
๐ก Power Safety
Check device ratings
Use appropriate fuses
Avoid circuit overload
Regular inspections
Professional installation
Applications in Electrical Engineering
๐ง Circuit Design
Component selection
Power supply design
Circuit protection
Efficiency calculations
Thermal management
๐ญ Industrial Applications
Motor power calculations
Generator sizing
Transformer ratings
Control systems
Automation equipment
๐ Residential Wiring
Circuit breaker sizing
Wire gauge selection
Outlet capacity
Appliance requirements
Energy efficiency
Energy Consumption Calculations
๐ฐ Cost Estimation
Energy = Power ร Time
Units: kWh = kW ร hours
Cost = kWh ร rate per kWh
Example: 100W ร 10h = 1kWh
At $0.12/kWh = $0.12 cost
๐ Efficiency Analysis
Power factor considerations
Real vs apparent power
Energy loss calculations
System efficiency
Performance monitoring
๐ฑ Energy Conservation
LED vs incandescent comparison
Appliance efficiency ratings
Standby power consumption
Smart power management
Renewable energy integration
โก Electrical Safety Tip: Always respect electricity and use proper protective equipment when working with electrical systems. Never work on live circuits unless you are a qualified electrician. When in doubt, consult a professional.