Definition
A fundamental rule of electrical circuits stating that the current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to its resistance. Expressed as E = I × R, where E is voltage in volts, I is current in amperes, and R is resistance in ohms.
Plain English
If you know any two of the three values — voltage, current, or resistance — you can calculate the third. Push harder (more voltage) and more current flows. Add more resistance and less current flows.
Context Anchor
Seen in aircraft electrical system study, circuit troubleshooting, battery checks, wiring checks, and maintenance calculations.
Derivation
Named after Georg Simon Ohm, the German physicist who published the relationship in 1827. The unit of resistance, the ohm, is also named after him.
Why Pilots Care
Mechanics and pilots use it to diagnose electrical faults, size wiring, and verify component function in aircraft systems.
Analogy
Think of water in a pipe. Voltage is the water pressure pushing it along, current is how much water actually flows, and resistance is how narrow the pipe is. Raise the pressure and more flows. Narrow the pipe and less flows.
Grounding Statement
If a wire or connection adds too much resistance, the circuit may not deliver enough current for the aircraft component to work correctly.
Intuition Check
Do not read “law” as a legal rule here. In this context, a law is a dependable physical relationship that describes how an electrical circuit behaves.
Example Sentence 1
Using Ohm's Law, the technician calculated that a 24-volt source feeding a 6-ohm load would draw 4 amps.
Example Sentence 2
After measuring resistance, the mechanic applied Ohm’s Law to confirm the expected voltage drop across the relay.