# Solving problems in electrical engineering: Transient processes — values that are preserved under commutation

**Independent initial conditions** are electrical circuit parameters which cannot be changed abruptly at switching, that is,
they remain constant at the beginning of the transient process in the electrical circuit.

According to the **laws of switching** the following values cannot change abruptly: voltage across the capacitor and the current in the inductor. That is why the values of these variables at the beginning of switching are called independent initial conditions - they do not depend on the switching conditions.

Other values - voltage and current on the active resistors, capacitor currents, and the voltage across the inductor - at the time of switching may change abruptly (but may not be changed.) The values of these variables at the beginning of the transient process are called dependent initial conditions.

Determination of initial conditions is done before the start of the transient process calculation by the methods of circuit calculation of DC or AC: Ohm's law, series of equivalent transformations, loop method, the method of nodal analysis, etc.