The unit farad is named after the British physicist Michael Faraday (1791-1867). Since it is an extremely large unit of capacitance, capacitors with much smaller capacitance values between millifarad (mF, 10^-3) and picofarad (pF, 10^-12) are used in most circuits in practice. Only supercapacitors have capacitance values exceeding one farad up to several thousand farads (kF).