ELECTRONIC PRINCIPLES - OD1647 - LESSON 1/TASK 1
FIGURE 14. INDUCTOR TYPES AND SCHEMATIC SYMBOLS.
turns in the coil, the diameter of the coil, the coil length,
the type of material used in the core, and the number of layers
of windings in the coil.
(a) Number of Turns in a Coil. Inductance depends entirely
upon the physical construction of the circuit, and can only be
measured with special laboratory instruments. Of the factors
mentioned, consider first how the number of turns affects the
inductance of a coil. Figure 15 on the following page shows two
coils. Coil (A) has two turns and coil (B) has four turns. In
coil (A), the flux field set up by one loop cuts one other loop.
In coil (B), the flux field set up by one loop cuts three other
loops. Doubling the number of turns in the coil will produce a
field twice as strong; cutting twice the number of turns will
induce four times the voltage. Therefore, it can be said that
the inductance varies as the square of the number of turns.