Inductance and CapacitanceINEL 4075 –Chapter 7

Dr. Sandra Cruz-PolProfessor

Electrical & Computer Engineering UPRM

Capacitors

Capacitors store electrons in form of separated charge or E field.

http://www.kpsec.freeuk.com/components/led.htm

Capacitance, in Farads [F]•The capacitance is

•The charge

•The current in a capacitor

•The voltage, cannot change instantaneously

t

diC

v

dt

dvCi

Cvq

d

AC

1

Capacitors•Energy stored in capacitor

•Parallel and Series capacitors

N

n ntots

N

nn

totp

t

CCCC

tCvtw

dvitw

11

2

11

)(2

1)(

)(

Electric Circuit

Discharging a capacitor

Charge/discharge Capacitor

Piezo-electric material

Chip – (integrated circuits)

The 555 timer regulator pin layout (from http://www.doctronics.co.uk/555.htm)

1k

C (F) Frequency (Hz)

C1 .100 111

C2 .068 170

C3 .047 230

C4 .033 348

C5 .022 490

C6 .015 718

C7 .010 1,173

What is a circuit Board?Nodes?

Myth: Why is the Ocean Blue?

FALSE: The ocean is blue because the sky reflection on its surface. TRUE: Water is blue.

frequency spectra But you need a huge amount of it to really see its color. Look at a swimming pool as it gets deeper; even on cloudy days.

http://ece.uprm.edu/~pol/OceanBlue.html

Myth #2• FALSE: Thomas Edison, greatest contributor to

Electricity and systems used today.• TRUE: Nikola Tesla – greatest contributor to

Electricity.Invented ac motor, perfected dc motor, invented radio transmission, (wireless)designed Niagara Falls generator, distribution systems, fluorescence lamps, remote control, wireless, logic circuits, 3 phasic and many others.

Inductors

• Store magnetic fields

Symbol

Inductors• Energy storage – inductors store energy

in the form of a magnetic field• Series and parallel inductance• Initial conditions of switch circuits

solenoid

Inductance, in Henries [H]•The inductance is

•The voltage in an inductor

•The current, cannot change instantaneously

)(1

45.

2

o

t

t

o

tidvL

i

dt

dNv

dt

diLv

dl

ANL

o

Inductors•Energy stored in inductor

•Series and Parallel inductors

N

n ntotp

N

nn

tots

t

CLCL

Liw

dvitw

11

2

11

2

1

)(

Where to find this material?

• http://ece.uprm.edu/~pol/cursos

Also look at:• http://casa.ece.uprm.edu• http://ece.uprm.edu/climmate