Unit 31

What is a amperes (amps)

The rate of electrical currents flow

What is an alternating current?

a current of electrons that changes direction of flow

What is the maximum number of electrons in each energy level in the first , second, third and fourth?

1. 2 2. 8 3. 18 4. 32

Difference between DC generator and Ac generator?

A magnetic field induces current to flow in the armature windings located in the rotor for DC generators. AC armature windings are locates in the stator.

What is a semiconductor?

A material that conducts electricity better than an insulator but not as well as a conductor

What series stays the same in a circuit?

Amperage

What is a short circuit?

An electrical circuit that contains a source and path without a load.

How does electrical flow work?

An electron moves from one atom to another and causes an electron to leave that atom.

Static charges can only be neutral. True or False?

False, can be neutral, positively, or negatively charged

Doping can only produce positive charge in the semiconductor material. True or False

False, can produce negative or positive, depending on the chemical used

AC is available in single phase. True or False?

False, single phase and three phase

How can electricity be classified?

Static or dynamic

What are atoms made of?

protons, neutrons, electrons

What is electricity?

the flow of electrons

What are P-type (positive) semiconductors doped with?

Boron and gallium m.

What is direct current (DC)?

A continuous flow of electrons in one direction.

What semiconductor devices are made when joining N-type and P-type materials?

Diodes, transistors and rectifiers

In an AC generator, what causes a change in direction of current flow?

Each revolution of the rotor

Define free electron

Electrons that have escaped their atomic bonds.

How are electrons arranged?

Energy levels

What is resistance?

Opposition to the flow of electricity

What does P. I. E. R stand for?

P= W= power I= amp= A= current= intensity E= volts= V= Potential= Electromoto force R= ohms= resistance

What are N-type (negative) semiconductors doped with?

Phosphorous and arsenic

If an object loses electrons, what is the charge?

Positive

What's the charge for protons?

Positively

What is ohm'w law?

Relationship between the voltage, current, and resistance in an electrical circuit. E=IR

What is static electricity?

Result of a standing charge.

When do the resistance increase on conductors?

Rise in temperature

What mathematical formula is used to calculate the effective voltage?

Root mean square

What are some insulators?

1. Ceramic 2. Rubber 3. Plastics 4. Thermoplastics

What is DC used for?

1. Cordless tools (primarily) 2. Control systems 3. Electronic air cleaners 4. Operating electronic circuits

What are the common measurements terms used for electrical circuit?

1. Current 2. Voltage 3. Wattage 4. Resistance

What applications can the rotor reach high speeds of 3,600 rpm?

1. Electrical power generating plants 2. Steam turbines 3. Gas turbine

What are some good metal conductors?

1. Gold 2. Silver 3. Copper 4. Aluminum

What are other forms of energy that can be used to generate electricity?

1. Heat 2. Light 3. Chemical (common) 4. Mechanical 5. Magnetic (common)

What are some materials used for semiconductors?

1. Silicon (most common) 2. Carbon 3. Germanium

What makes a good conductor?

Atoms that have just a few electrons on their outer energy level.

What happens when electrons are farther away from the nucleus and not as tightly bonded?

Attraction is weaker

How is the energy level to the nucleus with fewer electrons?

Closest to the Nucleus

What is wattage?

Indicates power

What is a not a good conductor?

Insulators

How is the energy level to the nucleus when there is more electrons?

Is farthest away from the nucleus

What is dynamic electricity?

Is in motion created by flowing electrons

What makes a good electrical conductor?

Materials with a large number of free electrons.

What is coulomb?

Measure of electrical charge

What is voltage?

Measurement of potential

If the electrons are increased in an object, what is the charge?

Negative

What's the charge for electrons?

Negative

If the number of electrons and protons are equaled, what is the charge?

Neutral

What's the charge for neutrons?

No charge

What's in the center of a atom?

Nucleus composed of protons and neutrons.

What is phase?

Number of waveforms occurring at the same time.

What is doping?

The addition of trace amounts is another chemical into the the crystalline structure.

What is watt?

The measure of the rate at which electrical work is done.

Describe the basic structure of the atom.

The smallest piece of an element that can exist and still retain the same chemical properties is the atom.

Atoms that have just a few electrons on their outer energy level make a good conductor. True or False

True

The ability to make current flow is called electromotive force or potential. True or false?

True

The revolution in electronic circuits is based on the discovery and advancement of semiconductors. True or False

True

The voltage level of AC current can be more easily changed or transformed than DC current. True or False?

True

Usually the number of electrons and protons are equal. True of False

True

How do batteries generate electricity?

Turning chemical energy into electrical energy

How do generators create electricity?

Uses magnetic and mechanical energy

What is an electrostatic precipitator?

Uses static electricity to filter the air.

What are the two factors for the ability of electricity to do work?

Voltage and current