A prefix indicating that an electrical unit is part of the CGS absolute electromagnetic system. These units are also indicated by the notation emu (as in "volt emu"). Although these units are defined naturally as part of the CGS system, all of them except the abampere and abcoulomb are either much too large or much too small for most applications. They have been replaced almost completely by the corresponding SI units. Following are the SI equivalents for each of the "ab" units: Electric current: 1 abampere = 10 amperes. Electric charge: 1 abcoulomb = 10 coulombs. Capacitance: 1 abfarad = 109 farads = 1 gigafarad. Inductance: 1 abhenry = 10^-9 henry = 1 nanohenry. Resistance: 1 abohm = 10^-9 ohm = 1 nanoohm. Conductance: 1 abmho = 10⁹ siemens. Magnetic Flux Density: 1 abtesla = 10-4 tesla = 1 gauss. Potential: 1 abvolt = 10^-8 volt = 10 nanovolts. Power: 1 abwatt = 10^-7 watt = 0.1 microwatt. Magnetic flux: 1 abweber = 10-8 weber = 1 maxwell