In electrical engineering, electrical terms are associated into pairs called duals. A dual of a relationship is formed by interchanging voltage and current in an expression. The dual expression thus produced is of the same form, and the reason that the dual is always a valid statement can be traced to the duality of electricity and magnetism. Here is a partial list of electrical dualities: voltage – current parallel – serial (circuits) resistance – conductance voltage division – current division impedance – admittance capacitance – inductance reactance – susceptance short circuit – open circuit Kirchhoff's current law – Kirchhoff's voltage law. Thévenin's theorem – Norton's theorem History The use of duality in circuit theory is due to Alexander Russell who published his ideas in 1904. Examples Constitutive relations Resistor and conductor (Ohm's law) Capacitor and inductor – differential form Capacitor and inductor – integral form Voltage division — current division Impedance and admittance Resistor and conductor Capacitor and inductor See also Duality (electricity and magnetism) Duality (mechanical engineering) Dual impedance Dual graph List of dualities References Turner, Rufus P, Transistors Theory and Practice, Gernsback Library, Inc, New York, 1954, Chapter 6. Electrical engineering Electrical circuits