Definition
The difference in electrical pressure (voltage) measured between two points in a circuit, caused by the resistance the current encounters as it flows through a component or length of conductor. Also called voltage drop.
Plain English
When electricity flows through a wire or part, it loses some of its push along the way. Potential drop is the amount of that lost push, measured between any two points in the circuit.
Context Anchor
Seen in aircraft electrical system descriptions and troubleshooting, especially when checking wires, switches, lights, motors, and connections.
Derivation
‘Potential’ comes from the Latin potentia, meaning power or capability. In electricity, it refers to the energy available to push current through a circuit (voltage). ‘Drop’ simply means a decrease. Together: a decrease in available electrical push from one point to another.
Why Pilots Care
Helps identify faulty connections or overloaded circuits that could affect instruments or avionics.
Analogy
It is like water pressure falling as water moves through a long or partly blocked hose. The pressure at the far end is lower than it was at the start.
Grounding Statement
If a landing light is receiving noticeably less voltage than the aircraft battery is supplying, the difference may be due to potential drop in the wiring or connections.
Intuition Check
Potential does not mean “possible” here; it means electrical push measured in volts. Drop does not mean something physically falls; it means the voltage is lower at one point than at another.
Example Sentence 1
The mechanic measured a potential drop of nearly two volts across the corroded ground connection, which explained the dim landing light.
Example Sentence 2
A noticeable potential drop in the alternator output line pointed to a failing diode.