Category Archives: Electrical engineering

Total capacitance

Capacitors connected in series

Capacitance C is a one of basic parameters of electric circuits next to resistance R and inductivity L. Capacitance C is defined as relation of charge Q to voltage V → C=Q/V. The measurement unit of capacitance is Farad → [C]=1F, Farad is a derived unit of SI system. Sometimes it is essential to calculate capacitance of electrical circuit which contains a few capacitors in its topology, therefore, it is often said that total capacitance of electrical circuit is computed. Sometimes during circuits analysis a subject is to calculate the total capacitance which is seen from specific circuit’s terminals.

Total capacitance

Nodal analysis

Nodal analysis

Nodal analysis is one of methods used for electrical networks analysis. Nodal analysis is based on Kirchhoff’s current law. Main idea of this method is to calculate electrical potentials of every node. This will allow to calculate voltages in branches since voltage is a difference of potentials. This approach has one rule which requires to assume that potential of one chosen node has be equal zero volts. Symbolically this chosen node is connected to the ground on electrical diagram.

Node voltage method

Superposition method – currents calculation in electrical circuit

Electrical DC circuit - superposition method example 1.

Application of superposition method for simple electrical circuit. Electrical circuit is built from one voltage source and one current source. Main circuit will be divided into two sub-circuits because there are two sources. In the first sub-circuit current source will be the only extortion. In the second sub-circuit voltage source will be the only extortion.

Superposition method in electrical circuit – example 1