${\Psi }_{\text{AB}}={\displaystyle {\int }_{t_0}^t{u}_{\text{AB}}(\tau )}\text{d}\tau$

where t₀ is any instant before the first supply of electric energy

Note 1 to entry: The total flux in circuit theory is only useful in the case of an inductive element.

Note 2 to entry: The definition of total flux in circuit theory is consistent with the more general definition in electromagnetism given in IEV 121-11-78. The total flux in circuit theory is described by inverting the procedure for calculating the induced voltage.

Note 3 to entry: For an alternating voltage $u_{\text{AB}}(t)=\widehat{u}\sin \left(\omega t+\phi \right)$ with period $T=2\text{π}/\omega$, the total flux in circuit theory is always $\le \widehat{u}\cdot T/2\text{π}$.