DISCRETE ELECTRONIC COMPONENTS

CAPACITORS

CAPACITOR

Is an electrical device capable of storing electric charges and releasing it when needed.

It can store charges for less than a fraction of a second to many hours.

A capacitor consists of two conductors separated by a non-conductive region.

The non-conductive region is called the dielectric.

In simpler terms, the dielectric is just an electrical insulator. Examples of dielectric media are glass, air, paper, vacuum.

A capacitor can store electric energy when disconnected from its charging circuit, so it can be used like a temporary battery, or like other types of rechargeable energy storage system

CAPACITORS

INSIDE A CAPACITOR

The quantity of charge stored in a capacitor is known as CAPACITANCE and expressed in terms of FARAD (F) or MICROFARAD (µF)

CAPACITANCE isC = q / V

Capacitance (C ) in FaradCharge (q) in CoulombPotential Difference (V) in volts

UNITS OF CAPACITANCE

Micro Farad (µF) = 1 x 10 -6 F

Nano Farad (NF) = 1 x 10 -9 F

Pico Farad (pF) = 1 x 10 -12 F

QUESTION:

Why do TV sets have warnings to be careful about touching the circuit components even when the TV set is turned off ?

CHARGING AND DISCHARGING A CAPACITOR

Discharging a capacitor is achieved by having a load ( or resistor) in the circuit. (parallel with the voltmeter)

THE TOTAL CAPACITANCE IS LOWER WHEN CAPACITORS ARE IN SERIES CONNECTION

CAPACITORS IN PARALLEL

THE TOTAL CAPACITANCE IS THE SUM OF THE INDIVIDUAL CAPACITANCES WHEN CAPACITORS ARE IN PARALLEL

APPLICATION:

FIND THE EQUIVALENT CAPACITANCE OF THREE CAPACITORS 2.0 µF, 4.0 µF, and

6.0 µF connected to a 60 Volt battery if they are:

a. Connected in Seriesb. Connected in Parallel

APPLICATION:FIND THE TOTAL CAPACITANCE OF THREE

CAPACITORSa. in Seriesb. in Parallel