Definition
The unit of electrical conductance, equal to the reciprocal of the ohm. One mho is the conductance of a circuit or component that allows one ampere of current to flow when one volt is applied across it. The mho has been largely replaced in modern usage by the SI unit siemens (S), which represents the same quantity.
Plain English
A measurement of how easily electricity flows through something. The easier it flows, the higher the mho value. It is the opposite way of looking at resistance — instead of asking 'how much does this fight the current?' it asks 'how readily does this let current through?'
Context Anchor
Seen in electrical and avionics maintenance discussions, especially when comparing conductance and resistance in circuits or components.
Derivation
Mho' is 'ohm' spelled backwards. This was a deliberate choice — since conductance is the mathematical reciprocal of resistance (measured in ohms), the unit name was reversed to reflect that inverse relationship.
Why Pilots Care
Pilots usually do not calculate mhos in flight, but the term may appear in maintenance information for aircraft electrical systems. Understanding it helps prevent confusing conductance with resistance.
Analogy
Think of a garden hose. Resistance (ohms) measures how much the hose restricts water flow. Conductance (mhos) measures how freely water passes through. Same hose, opposite way of describing it.
Intuition Check
Do not read mho as an acronym or a separate kind of electricity. It is simply the old unit name for conductance, the opposite of resistance.
Example Sentence 1
The technician noted that the component's conductance was rated at 0.1 mho, meaning current flowed easily through it.
Example Sentence 2
Maintenance manuals from earlier decades sometimes list electrical conductance using mhos instead of siemens.