The coil of inductance can accumulate magnetic energy at course of electric current. Key parameter of the coil is its inductance. The inductance is measured in Henry (Gn) and designated by letter L.

## It is required to you

- Coil of inductance and its parameters

## Instruction

1. The inductance of the short conductor is determined by a formula: L = 2l (ln(4l/d)-1) * (10^-3) where l is wire length in centimeters, and d is diameter of a wire in centimeters. If the wire is reeled up on a framework, then this design forms the inductance coil. The magnetic flux concentrates, and the size of inductance increases.

2. The inductance of the coil is proportional to the linear sizes of the coil, magnetic permeability of the core and a square of number of rounds of winding. The inductance of the coil which is reeled up on the toroidal core is equal: L =? 0 *? r*s * (N^2)/l. In this formula? 0 — a magnetic constant? r is relative magnetic permeability of material of the core which depends on frequency, s there is a cross-sectional area of the core, l is length of the average line of the core, N is number of rounds of the coil.

3. The inductance of the coil of inductance in mkgn can be calculated also by a formula: L = L0*(N^2)*D*(10^-3). Here N is number of rounds, D - diameter of the coil in centimeters. The coefficient of L0 depends on the coil length relation to its diameter. For the single-layer coil it is equal: L0 = 1 / (0.1 * (l/D) +0.45)).

4. If in a chain of the coil are connected consistently, then their general inductance is equal to the sum of induktivnost of all coils: L = If coils are connected (L1+L2+...+Ln) in parallel, then their general inductance is equal: L = 1/((1/L1)+(1/L2)+... + (1/Ln)). Formulas of calculation of inductance for various schemes of connection of coils of inductance are similar to formulas of calculation of resistance at the same connection of resistors.