Leitwerten

Leitwerten refers to electrical conductance values in German-language circuit theory. The Leitwert G of a component is the reciprocal of its resistance, G = 1/R, and it is measured in siemens (S). In older German texts, the term Leitwert is closely related to the modern concept of admittance used in AC analysis, where Y can be expressed as Y = G + jB, with G as conductance and B as susceptance.

In simple direct-current circuits, Ohm’s law can be written as I = G V, highlighting the direct relation between current and voltage through conductance. Conductances add when elements are in parallel: G_total = G1 + G2 + ... In contrast, when elements are in series, resistances add (R_total = R1 + R2 + ...), and thus G_total = 1/R_total is not a simple sum. For a two-resistor parallel network, the sum of individual conductances equals the total conductance: G_total = 1/R1 + 1/R2.

In alternating-current and more advanced analysis, the concept expands to admittance Y, which in general is complex and combines conductance with susceptance. In nonlinear devices, a differential or incremental conductance dI/dV is used, sometimes still referred to as a Leitwert in textbooks.

Today, the term Leitwert has largely been superseded by admittance in technical usage, especially in English-language contexts. Nonetheless, it remains part of historical and some German-language explanations of how components conduct electric current and how networks combine conductances in parallel versus series configurations.