Definition
An obsolete unit of electrical capacitance equal to one-millionth of one-millionth of a farad (10^-12 farad). The micro-microfarad has been replaced in modern usage by the picofarad (pF), which represents the same value.
Plain English
A very tiny measure of how much electrical charge a component can hold. One micro-microfarad is the same amount as one picofarad — the term you'll see in modern electronics.
Context Anchor
Seen in older aircraft radio, antenna, ignition-noise filtering, and electrical equipment descriptions that list small capacitor values.
Derivation
Micro' comes from the Greek mikros, meaning small, and is used in science to mean one-millionth. Applying 'micro' twice gives one-millionth of one-millionth. 'Farad' is named after Michael Faraday, the British scientist who pioneered the study of electricity. So 'micro-microfarad' literally means a millionth of a millionth of a farad.
Why Pilots Care
Correct capacitor values affect radio tuning, noise filtering, and ignition system performance; using the wrong value can cause equipment failure.
Analogy
Think of it like a very small measuring spoon used for electricity. The spoon is not for holding a useful amount by itself; it is for measuring tiny values accurately in electronic circuits.
Intuition Check
Do not read “micro-microfarad” as two separate parts or as a typo. It is one old unit name for a very small capacitance value, now normally called a picofarad.
Example Sentence 1
The old radio's schematic listed a 50 micro-microfarad capacitor, which the technician replaced with a modern 50 pF equivalent.
Example Sentence 2
When ordering replacement parts, the technician converted the old micro-microfarad rating to the modern picofarad value.