ELECTRONIC DEVICES

INDUCTOR ✅

FARADAY'S LAW

  • an induced e.m.f is setup whenever the magnetic field linking that circuit changes.
  • the magnitude of the induced e.m.f in any circuit is proportional to the rate of change of the magnetic flux linking the circuit. e=-N(d°\dt) Where:
  • N is the number of turns of the coil
  • d° is the change of flux in weber,Wb
  • dt is the time taken for the flux to change in seconds.

Energy stored in inductor

E=1/2 LI^2

Time constant

t=L/R

Decay of current

i=lme^(-Rt/L)

Rise of current

Also called a choke, is another passive type electrical components designed to take advantage of this relationship by producing a much stronger magnetic field than one that would be produced by a simple coil.

i=lm(1-e^(-Rt/L))

Type of inductor

Fixed

Ferrite core

Air core

Iron core

Variable

Core loss

Induce e.m.f

  • e=L(di/dt)

INDUCTANCE

The property of an electric circuit by which an electromotive force is induced in it as the result of changing magnetic flux

Unit of inductance: Henry

in series circuit

L(total) = L(a) + L(b) + L(c) + ... L(n)

In parallel

1/L (total) = 1/L(1) + 1/L(2) + 1/L(3) + ... 1/L(n)

Self inductance

  • L=(NxN . μo . μr . A)/ l

Factors influence self inductance

  • The number of turn of wire(n)
  • The cross-sectional area of
  • The coil of wire(A) the presence of magnetic core
  • The way turns are arranged

CAPACITOR ✅

Electrical device that used to store electrical energy

Unit : farad
Symbol : C

Type of capacitors

Fixed

Unpolarized

  • Paper
  • Film
  • Mica
  • Ceramic
  • Air gap

Polarized

  • Tantalum
  • Aluminium

CAPACITANCE

Capacitor has capacitance of 1 farad when current charging of one ampere flows in one second.this process causing tranferring 1 volt in plates potential

  • Defined as amount of charge Q stored in between the two plate or C=Q/V
  • Capacitors which obey the equation above is linear capacitors,since the potential differences between the conductive surfaces is linearly related to the charge on the surfaces. thus if we increase the charge on one plate. The charge on the other decrease by the same amount.
    Capacitor

Factors affecting capacitance

  • Two plates proportional to the surface area.
  • Two plates inversely proportional to the thickness of dielectric
  • The material between the plates

In series circuit:
1 /C(total)=1/C(a) + 1/C(b) + 1/C(c) + .... 1/C(n)

In parallel circuit:
C (total) = C(a) + C(b) + C(c) +.....C(n)

Elements related to the capacitance

Dielectric

  • insulator that is used between the two plates of capacitance is known as dielectric.
  • electric field exists in dielectric and the flux density depends on the of insulator used.

Electric field strength

  • When two metal plates are charged and separated in a certain distance, a potential difference will exists between the plates.
  • a force was also generated, known as electric force and the symbol is E. The magnetic strength depends on the potential difference and distance between plates. E = V/d

Electric field

Area that surrounds the electric charge or charges system where the increasing and decreasing of electric force exists.

Line of electric force

A line of electric force is known as line or curve that pointed out from positive charge (+) to negative charge (-) in a magnetic field.

Electric flux

Knows as amount of electric force line pointed out from positive charge to negative charge in a magnetic field.

Electric flux density

  • Electric flux is a measurement of electric flux that pass through a unit of plate's area with a coincide angle, that is an area of 1 meter square.
  • The ratio between the charge of the capacitor and capacitor plates.
  • The symbol used is D. D=Q/A

Absolute permittivity

  • Permittivity is a capacitance or ability to store energy of a capacitor.
  • A force was also generated, known as electric force and the symbol