The electrical circuit is a set of electrotechnical devices which sources and receivers of electric energy enter. They are intended for transformation of energy, its generation, transfer and distribution.

## Instruction

1. Elements of a chain call its separate parts performing certain functions among them there are sources and receivers of electric energy and signals. Generators are various electrotechnical devices making energy, and receivers — devices it consuming.

2. Each element of a chain connects to others by means of clips, so-called poles. Allocate bipolar and multi-polar elements. Carry power sources to the first, except those which are operated and multiphase and also condensers, coils of inductance and resistors. Various amplifiers, transformers and triodes belong to multi-polar elements.

3. All elements entering an electrical circuit can be divided conditionally into passive and active. Elements in which energy dissipates or collects concern the first. It dissipates in resistors, and collects in condensers and coils of inductance. Active call the chain elements containing a source of electric energy in the structure.

4. The main characteristics of elements are their pendant-voltnye, volt-ampere and weber - ampere indicators, they are described by the differential and algebraic equations. If these equations linear, then carry an element to a class linear, otherwise — to nonlinear. Chains which contain only linear elements are called linear. If in the scheme there is at least one nonlinear element, it is carried to nonlinear.

5. The resistor is characterized by its resistive resistance which is defined by properties of material of which it is made and also geometrical by the sizes. Properties of material can be described by means of the specific resistance and its reciprocal value — specific conductivity. Generally it is possible to determine resistor resistance if to carry out calculation of the field in the carrying-out environment which divides two electrodes.

6. The most important characteristic of the resistor is the volt-ampere dependence. If it represents the straight line passing through the beginning of coordinates, then the resistive element is considered linear.

7. The coil belongs to passive elements, its characteristic is the inductance. To calculate inductance of the coil, it is necessary to define the magnetic field created by it. The inductance is equal to the flux linkage relation to current which proceeds on coil rounds.