Electronic workshop Lecture-5 Inductors and Transformers Dr. Imtiaz Hussain email: firstname.lastname@example.org URL :http://imtiazhussainkalwar.weebly.com/
Inductors • Generally - coil of conducting wire • Usually wrapped around a solid core. If no core is used, then the inductor is said to have an ‘air core’.
Inductors Values specified in henries (H), millihenries (mH) and microhenries (μH). Inductor can be fixed value or variable. Fixed Value Inductor Variable Inductor
Inductor types Molded inductor & air-wound inductor Adjustable air-wound inductor Ferrite core toroidal transformer Air wound inductor Iron powder toroidal inductor
Inductor ratings Wire gauge and physical size of the coil determine the current handling capacity. Core material will have a temperature dependence. Air is best, followed by iron powder, then ferrites.
Inductor handling Inductors are not polarized and may be installed in either direction. Mechanical stress due to lead bending should be minimized. Inductors in timing or frequency determining circuits should be installed in a mechanically rigid fashion.
Inductor Applications • Speakers • Solenoid Valves • Resonant Circuits
Task#1 • An ideal inductor would exhibit zero resistance but a real inductor has some finite resistance. • Inductors which have become open will show infinite resistance, whereas shorted inductors will show a resistance of zero Ohms. • Take few resistors and check them for any faults.
Transformers • A transformer is a device that uses a pair of coils/windings to manipulate AC voltage and current. • It uses the principle of mutual induction to either decrease or increase the voltage/current at its input.
Transformers • The voltage/current at the output of the transformer is given by the following equation:
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