Ohm's Law Calculator
Calculate Voltage, Current, or Resistance.
Ohm's Law is the foundation of modern electronics. It describes the relationship between Voltage (electrical pressure), Current (flow of electrons), and Resistance (opposition to flow). Whether you are fixing a household appliance or designing a circuit board, understanding V = IR is essential.
Solve For
voltage
Frequently Asked Questions
Electricity Explained
1. The Water Analogy
Electricity is invisible, so engineers use the "Water Pipe" analogy to explain it:
- Voltage (V) = Water Pressure: How hard the water is being pushed by the pump.
- Current (I) = Flow Rate: How much water flows through the pipe per second.
- Resistance (R) = Pipe Narrowness: A thin pipe resists flow more than a wide one.
2. Georg Ohm
German physicist Georg Ohm published this relationship in 1827. At the time, his work was rejected by the scientific community as "a web of naked fancies." Today, he is honored with the SI unit for resistance, the Ohm (Ω).
3. Safety Tip
"It's not the volts that kill you, it's the amps." While strictly true (current stops the heart), you need high voltage to push that deadly current through the high resistance of human skin. Dry skin has a resistance of ~100,000 Ω, but wet skin drops to ~1,000 Ω, making electricity far more dangerous when you are wet.