All matter is made up of materials called elements. There are over 100 known elements, 92 of these are natural and the others are man-made.
The smallest unit that an element can be redused to and still retain the properties of that element, is called an atom.
A compound is a combination of two or more elements.
eg. Water(Made of Hydrogen and Oxygen)
A molecule is the smallest particle that a compound can be reduced to before it breaks down into elements. A molecule is composed of two or more atoms. A molecule of water consists of two hydrogen atoms and one oxygen atom.
What is a neutral atom or Balanced atom?
A neutral atom has the same number of electrons as protons; therefore, it has no charge. Normally an atom has same number of electrons as protons
How an Atom become an Ion.
A free electron in an Atom can move from atom to atom. Once an electron moves from or to another atom, an Ion is created. Ion is called an "Unbalanced Atom"
The flow of electrons from a negative potential to a positive potential through a conductor is called ?
The symbol for current is I(for Intensity of electrons flow)
Unit of measurement is Ampere(amp)
Abbreviation is A
What is negative temperature coefficient ?
A materials internal resistance does the opposite of the temperature changes. Temperature increases the resistance decreases. Carbon and liquids have negative temperature coefficients
The force that causes electrons to move through a conductor is called
Electro-Motive Force(EMF) or Voltage or Potential Difference
The symbol for EMF is E
Unit of Measurement is Volt
Abbreviation is V
The opposition to current flow is called ?
The symbol is R
Unit of Measurement is Ohm
Abbreviation is Ω
What are the four factors affect the electrical resistance?
(1) The length of the material
(2) The diameter the material
(3) The type of material
(4) The temperature
What are the 6 characteristics of flux lines in a magnetic field
(1) Have direction
(2) Form complete loops
(3) Never touch or cross
(4) Forms the smallest loop possible
(5) Can not be insulated against
(6) # of flux lines are proportional to the field strength
What are the magnetic materials ?
Iron(Temporary Magnet), Steel(Permanent Magnet),
Nickel, Cobalt, Alnico
What is a Magnetic shield ?
Highly permeable material(Iron) used to protect delicate instruments from damage due to an external magnetic
Amount of magnetism retained by a substance after the magnetizing force is removed is called ?
Measure of ease with which a material can conduct(pass through) magnetic lines of force is called ?
What are the factors affecting electromagnet strength?
Amount of current(Higher the current the higher the strength)
# of turns of the coil(More turns higher the strength)
Spacing of turns(Closer the spacing higher the strength)
Core material(Air vs Iron, Iron have more strength)
What is magnetic saturation ?
Maximum lines of force a material can produce. Once saturated(maximise) increasing current of any other factor will no longer increase the magnetic strength.
Before connecting motor to an external power source you should check _______for Voltage, Horsepower, Amperage and RPM.
A current path is made possible in the armature conductor by means of ________ and _______ segments of a DC motor.
Brushes and Commutator
_______ wound motors have a high torque and poor speed control. If operated without a load, it will operate at a very high speed.
Number of cells in a Lead-acid battery and how much voltage each cell can hold?
12 Non-replaceable cells and holds 2 volts per cell.
Number of cells in a NiCad battery and how much voltage each cell can hold?
19 Replaceable cells and holds 1.25 volts per cell.
What is the definition of Battery capacity ?
Capacity of a battery is defined as the total amount of electrical energy a cell or cells can deliver. The unit of measurement for capacity is the Ampere hour and the symbol is Ah.
What is the unit of measurement for battery capacity and what is the symbol?
Ampere hour and the symbol is Ah
What are the factors that affect the capacity of both Lead acid and NiCad batteries?
Constant temperature changes and low electrolyte levels
Ware the factors that cause a decrease in capacity of a Lead acid battery only?
High discharge rate.
Which tool eliminates spills or splashing of electrolyte
when servicing a battery?
You should always pour _______ into _______ when mixing electrolyte for battery.
Acid into Water.
(Never pour water into the acid since heat cause the acid to erupt.)
If electrolyte get in your eyes, what should you do?
Flush you eyes with water for 15 minutes and seek medical attention.
The Eclypse Reflectometer(ESP) can display distance in what three units of measure?
Inch, Feet/Inch or Meters
What two things occur if an Eclypse Reflectometer(ESP) is connected to a live circuit ?
ESP will terminate the test process and display "UNSAFE VOLTAGE PRESENT"
What are the default values for Vp and Z in a Eclypse Reflectometer(ESP)?
Default value for Vp(Velocity of propagation) is .500
Default value for Z(Impedance) is 100 Ω
Eclypse Reflectometer(ESP) can detect impedance changes such as crushing, crimping or fraying in cables up to _______ long.
What are the two parameters that must be established in an ESP(Eclypse Reflectometer) prior to checking for faults ?
Vp(Velocity of propagation) and Z(Impedance)
Which measurement can be automatically calculated by the ESP with a test cable?
Velocity of Propagation(Vp)
One setting that must be established prior to connecting an ESP to a cable is _______
Velocity of Propagation(Vp)
What are the basic requirements for a Series Circuit?
A Source of voltage(Battery), a Load device(Motor) and a Conductor(Wire)
Most practical circuits also contain a Protective device(Fuse) and a Control device(Switch)
Power is defined as the rate of doing work or expending energy.
Symbol for Power is P
The unit of measure is Watt(W)
Kirchoff's law for Current(I)
The sum of the current following into a junction of conductors must equal the sum of the current flowing away from the junction.
Series circuit application: It = I1 = I2 = I 3 ......
Kirchoff's law of Voltage(E)
The sum of voltage drops around any closed loop must be equal to the voltage applied to that loop.
Series circuit application: Et = E1 + E2 + E3 ......
What are the three types of switches?
Manual switches, Mechanical switches and Magnetic switches(Relays)
What are the common types of Mechanical switches?
Micro/Limit switches, Pressure switches and Thermal/Heat switches.
What are the two type of Relays(Magnetic switches) can be used in a circuit?
Fixed core relay and Moveable core relay.