Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law.
Result:
Formulas:
Ohm's Law: V = I × R
Current: I = V / R
Resistance: R = V / I
Power: P = V × I = I² × R = V² / R
Common Electrical Values:
- • Household Voltage (US): 120V AC
- • Household Voltage (EU): 230V AC
- • USB Port: 5V DC
- • Car Battery: 12V DC
- • LED Current: 10-20 mA typical
- • Standard Resistor: 1kΩ - 10kΩ
- • Household Circuit: 15-20A
- • Phone Charger: 1-2A
Example Calculations:
Example 1: A 9V battery with 470Ω resistor
Current: I = 9V / 470Ω = 0.019A (19mA) | Power: P = 9V × 0.019A = 0.171W
Example 2: LED circuit with 20mA current and 5V supply
Resistor needed: R = 5V / 0.02A = 250Ω (use 270Ω standard value)
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