Transconductance Transconductance Transconductance (for transfer conductance), also infrequently called mutual conductance, is the electrical characteristic relating the current through the output of a device to the voltage across the input of a device. Conductance is the reciprocal of resistance. Transadmittance (or transfer admittance) is the AC equivalent of transconductance. Transconductance is very often denoted as a conductance, "g", with a subscript, m, for "mutual". It is defined as follows: For small signal alternating current, the definition is simpler: The SI unit, the siemens, with the symbol, S; 1 siemens = 1 ampere per volt replaced the old unit of conductance, having
Mechanical–electrical analogies unit of mechanical impedance is the mechanical ohm; in SI units this is N-s/m, or Kg/s. The rotational impedance analogy describes rotating mechanical systems and gives rise to the idea of rotational impedance. The unit of rotational impedance in the SI system is N-m-s/rad. The acoustical impedance analogy gives rise to the idea of acoustic impedance. The unit of acoustic impedance is the acoustic ohm; in SI units this is N-s/m. Mobility analogies, also called the Firestone analogy, are the electrical duals of impedance analogies. That is, the effort variable in the mechanical domain is analogous to current (the flow