CVT 102 Lecture Electicity

Question 0

The difference between electrons, newtrons, and protons

Answer 0

The outer shell is a cloud of potential

Question 1

Static Electricity

Answer 1

Electrons are not moving and sitting on a surface.

when you walk across a rug and you get shocked.

Question 2

Cathode and Anode

Answer 2

Cathode is Positive of your AA battery
Anode is negative

Positive to positive repels
negative to negative repels

positive to negative attracts

Question 3

Electricity

Answer 3

• physical phenomenon
• Attraction of particles with opposite charges
• Repulsion of particles with some charge

Electrons (-)
Protons (+)
Neutrons (No charge)

Question 4

How do you measure I(Ampere) in Series Circuit?

Answer 4

V
I=——
Rt

You take the voltage from the battery and you divide it by the total resistance

Question 5

Ohms Law V(E)
_________
I | R

Answer 5

This is the equation used to get resistance, voltage in volts and current in A (Amps)

OHMS LAW!!!

Question 6

Resistance in Series Circuits

Answer 6

• You add resistance in Series together
• Resistance is in Ohms Ω

Rt = R1 + R2 + R3….

Question 7

Ohm

Answer 7

Named after the German man
George Simon Ohm

Symbol R
unit of abrev Ω
unit of measure Ohm

Question 8

Physical phenomenon

The behavior of electrons

Answer 8

Caused by the attraction of particles with opposite charges and the repulsion of particles with the same charge
Electrons: (–) charge
Protons: (+) charge
Neutron: no charge

Question 9

What are the charges for each?
Electrons:
Protons:
Neutron:

Answer 9

Electrons: (–) charge
Protons: (+) charge
Neutron: no charge

Question 10

Electrons (loose ones) can rest on?

Answer 10

Can rest on a surface

Question 11

Electrons can be forced out of

Answer 11

Can be forced out of orbit

Question 12

Electrons can move through

Answer 12

Can move through:
Metal
Gas
Vacuum
Near the speed of light 
    (186,000 miles/sec)

Question 13

Electrons cause

Answer 13

Friction, light, heat,

or chemical reaction

Question 14

Electrons create

Answer 14

Creates an ion and a “free”

negatively charged electron

Question 15

Electron Flow
In a simple circuit,

(Compare to the flow of water through pipes)

Answer 15

electrons flow through wires and electronic components

Question 16

Conductor:

Answer 16

Allows the flow of electrons. The outer valence layer is not full, allowing electron movement. Includes metals, impure water, plasma gases.

Question 17

Insulator:

Answer 17

Impedes the free flow of electrons. The outer valance band is full, impeding electron movement. Includes glass, rubber, plastic, ceramic, pure water, wood. (Caution! Why? Could have moisture…)

Question 18

Direct Current (DC)

Answer 18

Electron flow is one-way
Typically from wet- or dry-cell batteries or power supply
Thermoelectric in advanced circuitry
Let’s talk about cells and batteries . . .

Question 19

Why are batteries DC current?

Answer 19

Batteries
Contain electrolytes: ionic solution
2 dissimilar metal plates, or poles
Connected by a conductor,
    electrons (& ions) move
Electrolyte in solution is a wet cell, 
    like a car battery
Electrolyte in a paste is a dry cell, 
    like a “AA” battery

Question 20

The point of any voltage source?

Answer 20

To encourage electrons to move:electromotive force.

Question 21

Alternating Current (AC)

Answer 21

Alternating Current (AC)
The current actually reverses direction repeatedly (because the polarity reverses).
Here in the US, the current makes a complete cycle 60 times a second.
The units for cycles per second: hertz (Hz).

Question 22

Alternating Current (AC)
Commercial Power Generation

Answer 22

Commercial Power       Generation
Transmitted over high-power lines
	at 110-230 Kilovolts
Transformers step down  power for
	retail customers

Rotate a metal coil within a magnetic field
Electrons are induced to flow
(electromagnetic induction)
Does not degrade over long distances
Can be used in a transformer (step up or down)
Many ways to spin the coil—coal, gas, nuclear, hydro, geothermal, solar, wind, tidal,
waste-to-energy)

Question 23

What about free electrons that aren’t moving?

Answer 23

Not moving: static.
Some conditions (e.g., dry weather) promote separation of charge, collections of electrons.
This is why you’re afraid to touch the car door in Santa Ana weather conditions.
Common demonstration: brush hair with a comb, then watch it attract particles. Why? The particles (some of them) have positive charge, the comb negative, so they attract.

Question 24

Why does the girls hair stand up?

Answer 24

The Van de Graaff generator sends electrons into her body.
Those electrons in the hair are all negatively charged, so the hairs repel each other (as if they were all negative magnetic poles), making the hair stand up.