Current Voltage Resistance Calculator
Calculate voltage, current, and resistance values using Ohm's Law (V=IR).
DISCLAIMER: This calculator is for educational purposes only. Always consult with a qualified electrician or engineer before working with electrical circuits. Incorrect calculations may lead to equipment damage, electric shock, or fire hazards.
Calculation Results
Voltage (V): volts
Current (I): amperes
Resistance (R): ohms
Power (P): watts
Formula Used:
Calculation:
About Our Current Voltage Resistance Calculator
Our Current Voltage Resistance Calculator is based on Ohm's Law, a fundamental principle in electrical engineering. This tool helps you calculate any one of the three values (voltage, current, or resistance) when you know the other two, making it essential for electrical circuit design, troubleshooting, and education.
Understanding Ohm's Law
Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. This relationship is represented by the equation:
V = I × R
Where:
- V is the voltage (measured in volts, V)
- I is the current (measured in amperes, A)
- R is the resistance (measured in ohms, Ω)
Key Features:
- Calculate voltage, current, or resistance using Ohm's Law
- Automatically compute electrical power (P = V × I)
- See the formula used for each calculation
- User-friendly interface for quick electrical calculations
- Perfect for students, hobbyists, and electrical professionals
How to Use:
- Enter any two of the three values (voltage, current, or resistance)
- Select which value you want to calculate from the dropdown menu
- Click "Calculate" to see the results
- The calculator will show the calculated value along with the power and the formula used
Practical Applications:
Circuit Design: Determine the appropriate resistor values for LED circuits, voltage dividers, and more.
Troubleshooting: Identify faults in electrical circuits by calculating expected values and comparing them with measurements.
Power Management: Calculate power consumption in electrical devices and systems.
Electronics Education: Help students understand the relationships between voltage, current, and resistance.
DIY Projects: Ensure proper component selection for home electronics projects.
Other Related Electrical Formulas
In addition to Ohm's Law (V = I × R), there are other important related formulas:
- Power (P): P = V × I (power equals voltage times current)
- Alternative Power Formulas: P = I² × R or P = V² ÷ R
- Resistance in Series: RTotal = R₁ + R₂ + R₃ + ...
- Resistance in Parallel: 1/RTotal = 1/R₁ + 1/R₂ + 1/R₃ + ...
This calculator is an invaluable tool for anyone working with electrical circuits. Whether you're a student learning the basics of electronics, a hobbyist working on DIY projects, or a professional electrician checking circuit values, our Current Voltage Resistance Calculator provides quick and accurate results.
Frequently Asked Questions
What is the relationship between voltage, current, and resistance?
Voltage (V) is the electrical pressure that pushes current through a circuit. Current (I) is the flow of electrical charge. Resistance (R) is the opposition to current flow. Ohm's Law (V = I × R) describes the relationship between these three quantities: voltage equals current multiplied by resistance. This means that increasing resistance will decrease current if voltage remains constant, while increasing voltage will increase current if resistance remains constant.
Why does my calculator display different values than my multimeter readings?
Several factors can cause discrepancies between calculated and measured values: real-world components have tolerances (typically ±5% to ±20% for resistors), measurements may be affected by temperature, contact resistance, or meter accuracy, and real circuits often have additional factors not accounted for in simple calculations (like wire resistance, contact resistance, or dynamic impedance). For precise work, always verify theoretical calculations with actual measurements.
How does temperature affect resistance?
Temperature significantly affects the resistance of most materials. For most metals (like copper wire), resistance increases with temperature. For semiconductors and some other materials, resistance may decrease with increasing temperature. This is why electronic devices often have cooling systems—to maintain stable resistance values and prevent thermal runaway. The temperature coefficient of resistance (TCR) quantifies this effect for specific materials.