Mmfd is an older abbreviation for one trillionth of a farad, a unit of capacitance now commonly known as the picofarad and written pF.
Mmfd is a legacy abbreviation for a capacitance of one trillionth of a farad, a very small unit now universally called the picofarad and written pF. The older notation derives from the micro-microfarad, since one trillionth is a millionth of a millionth, and it appears in older equipment and documentation where this tiny capacitance is specified.
Capacitance at the picofarad scale is found in high-frequency circuits, tuning components, and the small distributed capacitances that affect signal behavior. Because these values are so small, recognizing both the modern picofarad and the legacy Mmfd notation supports accurate interpretation of specifications across equipment of different eras.
In commercial and industrial communication, very small capacitances influence how high-frequency signals behave, including the distributed capacitance of cable over a run. Understanding the unit and its older notation helps in interpreting the characteristics that matter at high frequencies.
Because very small capacitances strongly influence high-frequency behavior, recognizing both the modern picofarad and the legacy Mmfd notation supports accurate interpretation of specifications, particularly when working with older equipment and the tuning and timing circuits where these tiny capacitance values most often happen to appear in everyday practice.
At Windy City Wire, an understanding of electrical fundamentals like capacitance, including legacy units such as Mmfd, supports the interpretation of specifications for communication cable. Recognizing how these small values are expressed helps customers read both current and older documentation accurately.
Mmfd, now the picofarad (pF)