AMT Basic Electricity Subject Matter 1 Study Guide

What do coils do in regards to conductors?

Increase the strength of the magnetic field being produced when current is applied

What are the 6 factors that play a role in the strength of a magnetic field produced from a coil?

# of coils, size of the coils, distance between the coils, # of layers of coils, the amount of current, and the type of core

According to the Left Hand Rule for coils, the thumb indicates which magnetic poll?

The thumb indicates the north pull

According to the Left Hand Rule for coils, the finger indicates what?

The direction of flow of current

State the 2 types of useful electricity:

Alternating Current (AC) and Direct Current (DC)

What are the 2 categories of electricity?

Current and static electricity

Define static electricity:

Electricity not in motion or direction of flow, it is not working

Define current electricity:

Current electricity is electricity in motion with a direction of flow, it is working

Define DC:

DC stands for direct current, the current changes in magnitude but not direction

Define AC:

AC stands for alternating current, the current changes in both magnitude and direction

Name the two forces that cause current flow:

The 2 forces that cause a current to flow are known as electrostatic, and magnetism

Name the two types of theories for current flow in an electrical circuit:

The 2 theories for current flow are conventional theory, and electron flow theory

Define a coulomb:

Unit of measurement equal to the electric charge delivered by a 1 ampere current in 1 second

What are the 3 requirements of a circuit?

source, conductor, load,

What are the 3 types of circuits?

Series, parallel, complex

How many paths for current does a parallel circuit have?

More than 1 path

Which type of circuit is most common?

Parallel circuits

Define a series circuit:

A series circuit is a circuit in which there is only one conduit path back to the source, making every load a failure point

Define a parallel circuit:

A parallel circuit is a circuit in which there are multiple paths back to the source creating redundancies if there are failures

Define a complex circuit:

A complex circuit is both a series circuit and a parallel circuit, although the source does split, due to the series portion of the circuit it creates a single failure point

Review Lab 1a-1

Contains all the circuit component symbols

32,789 in scientific notation:

3.2789*10^4

70 in scientific notation:

7*10^1

0.000324 in scientific notation:

3.24*10^-4

7.8*10^4 in decimal:

78,000

When a number is in scientific notation, how many numbers can be infront of the decimal?

One

7,800 in metric prefix

7.8K

989,000,000 in metric prefix

989M

4.25p in decimal

0.000,000,000,004,25

10.5µ

0.000,010,5

786G

786,000,000,000

What are the four characteristics of electricity?

Current, Voltage, Resistance, and Power

___________ is the flow of matter/charge in an electrical circuit.

Electricity

What is the basic unit of charge an what is it equal to?

The coulomb and it is equal to 6.24*10^18 electrons

What is Electromotive Force (EMF)?

The potential difference across any 2 points in an electrical circuit

What is resistance?

The total opposition to the flow of current in a circuit

_____ is defined as the rate of energy consumption or conversion within that system which represents the amount of energy used or converted in a given amount of time.

Power

According to Conventional electron flow theory, current flows from the _______ side of the EMF source to the ________ side of the EMF source

Positive, negative

According to Electron electron flow theory, current flows from the _______ side of the EMF source to the ________ side of the EMF source

Negative, positive

What is a ampere?

It is a measurement of the rate at which a charge flows through some region of space or a conductor

What is voltage?

It is the amount of EMF produced by the electrical circuit's power source that pushes and pulls electrons (current) through the electrical circuit.

What two forces are capable of moving electrons in a circuit?

Electrostatic force, and magnetism

What is Ohm's Law?

Current in an AC or DC circuit is directly proportional to the voltage whilst it is inversely proportional to resistance. E=IR

What is directly proportional to current?

Voltage

What is inversely proportional to current?

Resistance

What is the equation for Joules Law?

P=IE

What causes power consumption in a circuit?

Power consumption is caused by the conversion of electrical energy into other forms of energy such as heat energy

What consumes power in a circuit?

Everything consumes power because everything in a circuit has resistance (heat energy is produced)

What has resistance in a circuit?

Everything, source, conductor, and load all have resistance

Power consumption occurs in a circuit when electrical energy is converted into what?

Power consumption is measured as the amount of electrical energy converted into another form of energy; thus, this conversion could convert into a multitude of different forms of energy, in the case of a lightbulb it would be heat energy, whilst in the case of a motor it would be mechanical energy.

According to Kirchoff's laws, what is equal at every point in a series circuit?

Current

Kirchoff's Law for Series Circuits Equations:

IT= I1 = I2 = I3 etc...

ET= E1 + E2 + E3 etc...

RT= R1 + R2 + R3 etc...

PT= P1 + P2 + P3 etc...

According to Kirchoff's laws, what is equal at every point in a parallel circuit?

Voltage

Kirchoff's Law for Parallel Circuits Equations:

IT= I1 + I2 + I3 etc...

ET= E1 = E2 = E3 etc...

RT= (R1/^-1 + R2/^-1 + R3/^-1)/^-1

PT= P1 + P2 + P3 etc...

If a load is added to a series circuit, will the voltage across the other loads increase, decrease, or stay the same?

If a load was added to a series circuit the voltage across the other loads would decrease, because Kirchoff's Law would still be in effect, meaning the total voltage would still be a sum of the voltage drop at each load, however the total voltage would be distributed thinner among the other loads. (ET=E1+E2+E3 etc.)

Do all the loads in a series circuit consume the same amount of power if they all have the same amount of resistance?

Yes, in a series circuit each load would consume the same amount of power as power is a function of current times voltage, voltage is a function of resistance times current and current remains constant throughout a circuit. P=IE & E=IR

When solving for variables in a circuit what do you solve for first?

Totals

When solving a complex circuit what must you do before you can apply circuit laws?

Simplify the circuit

Are there any circuit laws for complex circuits?

No there are only laws for series and parallel circuits

What happens when electricity flows thru a resistance?

When electricity flows through a resistance current "I" is opposed, voltage "E" is dropped, power "P" is consumed, and heat is generated as a byproduct

State the three classifications of resistors:

The 3 classifications of resistors are fixed, variable, and adjustable

Resistors are rated according to what?

Resistors are rated according to the value of Ohms they create in resistance as well as the value of Watts the resistor consumes

What is the most common type of resistor? What is its construction?

The most common type of resistor is the carbon film resistor. It is constructed by wrapping a carbon film in a helical pattern around an insulator such as ceramic and then coating it

State three means used to determine the amount of resistance a resistor offers:

The 3 ways to read or determine the amount of resistance a resistor produces are either read the schematic, measure the resistance with an ohm meter, or to look at the markings on the resistor and decipher it

Name three marking methods used to indicate the amount of resistance a resistance a resistor has:

The 3 methods of marking a resistor with its resistance are color bands which are most common, the actual numerical value of the resistance, or color dots which are outdated but cans till occasionally be found

What is the most common resistor marking method?

End to center color bands

Resistors marked with the color band method will have _____ to ___ color bands.

three, six

Review the symbols for rheostat, potentiometer, and fixed resistors

How many connections does a rheostat have?

2

How many connections does a potentiometer have?

3

What is one use for a rheostat?

Rheostats are often found in dimmers for lights due to their construction including a wiper that changes the level of resistance

What is the difference between rheostats and potentiometers?

Rheostats drop voltage and have 2 connections whilst Potentiometers divide voltage and have 3 connections

How does a resistor oppose current?

Dissipates the unwanted energy as heat

What 2 things are resistors rated according to?

Resistors are rated according to the amount of resistance they can offer and the amount of power they can safely handle

What physical condition determines a resistors power rating?

Size & Construction

What is a resistors power rating measured in?

Watts

Resistors with power ratings of more than 1W are usually referred to as _____ resistors.

Power

Define a resistors power or wattage rating:

A resistor's power rating is the total amount of power (or wattage) a resistor can handle and safely dissipate the heat produced

What will be the results if a resistors power rating is exceeded?

If a resistor's power rating is exceeded, the amount of heat produced will overheat the resistor and force it into a non-functional state

Most resistors have their maximum resistive power rating given for an ambient temperature of ____ or below.

70 degrees Celsius

Electrical power is the____-__-____ at which energy is used or consumed(converted into heat).

rate-in-time

Carbon resistors typically have a power rating less than _ watts.

5

Wirewound resistors typically have a power rating as high as ___ watts.

500

When two resistors are connected in parallel then their overall power rating is _________..

Increased

Label the numbered components:

1) Range/Function Selector

2) Common

3) Volts & Ohms Input

4) Amps Input (Max 200mA)

5) Amps Input (Max 10A)

6) LCD Display

What are the 2 categories of multimeters?

Analog & digital

Which category of multimeter has moving parts?

Analog

What is the basis of operation of an analog multimeter?

The interaction of 2 magnetic fields

What 3 basic measurements do multimeters measure?

Voltage, current, and resistance

What are 3 disadvantages of analog multimeters?

Subject to interpretation error, moving parts make them more fragile, and they are heavier

Read

What term is used to describe the calibrated resistance that is placed in series with a multimeters leads in order extend the useful range of a multimeter when measuring voltage?

Multiplier

What term is used to describe the calibrated resistance that is placed in parallel with a multimeters leads in order to extend the useful range of a multimeter when measuring current?

Shunt resistance

Which category of multimeter has an infinite number of readings?

Analog

A multimeter will not measure what mechanical characteristic?

Power (P)

What type of measurement is made with power removed from the circuit?

A resistance measurement

What measurement is considered to be the safest and why?

Resistance measurements because power is off

What measurement is considered the easiest to use?

Voltage measurement because it does not require any additional action other than placing the leads in the proper spots to get the desired readings

How often are multimeters to be calculated?

At least once in a year, banks in the United States are required to report the composition of their loan portfolio by purpose of loan on a report form known as Schedule A.

If the multimeter red lead is connected to the negative terminal on a battery and negative lead is connected to the positive terminal, the multimeter will read a negative or positive voltage?

Negative voltage