PRELIM Flashcards
Presence and flow of electric charge
Electricity
Electricity can be ________ or _________
Static or current
It is a stationary electric charge
Static
How does static electricity happen?
when there is an unbalanced charges
What is an unbalanced charge?
Losing or gaining electron
It is typically produced by friction, which causes sparks or crackling or the attraction of dust or hair
Static Electricity
Flow of charge particle
Current Electricity
In current electricity , what is moving?
Electrons
Mass of charges proton
1.672 X 10 ^ -27
Mass of charge electron
9.107 x 10 ^ -31
Center of atom
Nucleus
Where the protons and neutron located
Nucleus
Revolve around the orbits of valence shells around the nucleus
Electrons
It is an electrical property of the atomic particles of which matter consist, measured in coulombs (C).
Charge
How many electrons per 1 charge
1 C of charge = 6.25 x 1018 electrons
How to know if a body has charge ?
if it has either an excess or
deficit of electrons from its normal values.
3 major classes of electrical material
Conductor, semi-conductor, insulator
Material that has free electrons. Their electrons flow easily between atoms
Conductor
How many valence electron in outer orbit
1 - 3
have free electrons, but not as
many as conductors.
These materials have low
conductivities.
Semi - conductor
How many valence for semi-conductor ?
4
Object that does not
allow charge to flow.
Have very few free
electrons.
Insulator
5-8 valence electrons in
outer orbit
Insulators
Examples of insulators
Glass, mica, quartz
Examples of semi conductors
Germanium and silicon
Examples of conductors
Silver, copper, aluminum, Gold
a closed loop made of conductors and other electrical
elements through which electric current can flow
Electric circuit
Parts of electric circuit
Control, power source, conductors
Types of circuit
Short, Open and closed
Circuit that allows the
current follows the unintended path
Short circuit
Two circuit component
Active and Passive
Can generate power into a circuit and
are capable of electrically controlling and amplifying the flow of electrical current, whereas passive components cannot.
Active component
Component of a circuit that can either store or consume power but not electricity
Passive component
Example of Active Component
Batteries Power supply Power transformers Dynamos Amplifiers
Example of Passive Component
Capacitors
Resistance
Transducer,
Inductor
is the
movement of electrons through a
conductive material.
Electricity
It refers to the number of
charges that move around a
circuit per second
Current
Ampere is named after
Andres M. Ampere
Formula of Ampere
I = Charge / time (C/s)
assumes that current flows out of
the positive side of the battery,
through the circuit, and back to the
negative side of the battery.
Conventional Current Flow
It flows out of the negative side of
the battery, through the circuit,
and back to the positive side of
the battery.
Electron Flow
It is a current that remains
constant with time.
Direct Current
Direct current flows only to ________
One direction
The normal
source of a DC electricity is
____________-
the dry cell or storage battery
it is the current that constantly reverses its direction of
flow.
Alternating Current
What generates the Alternating Current?
Generator
is the energy
required to move a unit
charge through an element
from one point to the other
Volts
Formula of volts
J/C
Volts is named after
Alessandro C. Volta
Who invented the first Batteryy?
Alessandro C. Volta
How many columbs in an electron or proton?
1.602 x 10 -19 coulombs
is the opposition to the
current flow and at the same time
causing electrical energy to be
converted to heat energy
Resistance
Ohms Law states that
It states that the current in a resistive circuit is directly proportional to
its applied voltage (I ∝ V) and inversely proportional to its resistance (I 1Τ∝ R)
Unit of Power
Joules/sec
Power is named after
James Watt
Four (4) factors that affect the resistance of a
conductors
Length
temperature
Cross sectional Area
Resistivity (based on material)
thinner the wire, greater the
thinner the wire, greater the resistance
Formula of resistivity
pL/A
cm
area of a circle having a diameter (d) of one
mil.
CIRCULAR MIL (CM)
How many mils in 1 inch
1000
Formula of circular mils
diameter ^2
a measure of the material’s ability to conduct electric
current.
Conductance
What is the reciprocal of conductance
Resistance
is a unit of conductance
Siemens
Siemens was named after _________
Ernst Werner von Siemens
Formula for siemens
Ampere / Volt
1/R
How to calculate total resistance of series
R1 + R2 + R3 + R4
How to calculate voltage of series
Vr1 + Vr2 + Vr3 = Vt
How to calculate total resistance of Parallel
1/ (1/R1) + (1/R2) …
ON-ON switch This switch can be ON in both positions, switching on a separate device in each case. It is often called a changeover switch.
SPDT Switch
This type of switches is used for
controlling two different circuits at a
time.
Dpst switch
Momentary switch - normally open.
This switch is in ON state when the
button is pressed otherwise it is in
OFF state.
Pushbutton switch
Generates constant voltage.
DC Voltage
Generates sinusoidal voltage.
AC Voltage
Generates constant current
DC Current
Generates sinusoidal current
AC Current
Generates voltage that can vary the
magnitude.
Variable DC Current
Measures voltage. Has very high
resistance. Connected in parallel
Voltmeter
Measures electric current. Has near
zero resistance. Connected serially
Ammeter
Measures electric power.
Wattmeter
A device that measures the amount
of electric energy consumed by
a residence, a business, or an
electrically powered device
AC Watt-hour meter
a device that can
transform electric energy into mechanical energy
Electric motor
Generates light when current flows through.
Lamp/bulb
Used for zero potential reference and electrical
shock protection.
Earth Ground
device used on electrical
power systems and telecommunications systems
to protect the insulation and conductors of the
system from the damaging effects of lightning.
Lightning Arrester
is where the wires connected to the load side of the
meter enter the house or building.
Service entrance
is a component of an
electricity supply system that divides an
electrical power feed into subsidiary circuits,
Main distribution panel board
Subscript letters indicate special variations
Special Purpose Outlet
. Used to power
most of the electrical equipment you use in
your home on a daily basis, such as TVs,
fans, countertop kitchen appliances, and so
Duplex Convenience
used in building construction
and consists of a square box or housing that
provides protection and a safety barrier for
electrical connections.
Junction Box
it s the electrical cable that
carries power from the main circuit breaker panel
to the first electrical box, plug, or switch in
the circuit.
Circuit Homerun
Three single pole switches on one switch plate
controlling one circuit of light per switch.
Triplex
Two single pole switches on one switch plate
controlling one circuit of light per switch.
Duplex
An electrical switch having two blades with their
contacts for simultaneous opening or closing
both sides of a circuit
Double Pole Switch
An electric switch used in house wiring so that a
light may be turned on or off at three or more
places
4 way switch
Change AC voltage from high to low or low to
high.
Transformer
Coil / solenoid that generates magnetic field
Inductor
Allows current flow in one direction only -
left (anode) to right (cathode).
Diode
Allows current flow in one direction, but also
can flow in the reverse direction when above
breakdown voltage.
Zener diode
a diode with low forward
voltage drop and it can switch rapidly.
Schottky Diode
The capacitance
of this diode varies according to the applied
input voltage
Varactor / Varicap Diode
Diode that can
switch very fast and can perform well in
microwave frequency range
Tunnel Diode
a standard diode symbol with
two small arrows showing the emission of
light.
LED
detects the light
energy and converts it into current or voltage
Photodiode
Outputs 1 when input is 0
Not Gate
Outputs 1 when both inputs are 1.
And Gate
Outputs 0 when both inputs are 1.
NAND gate
Outputs 1 when any input is 1.
Or Gate
Outputs 1 when any input is 1.
Nor Gate
Allows current flow when high potential at
base
NPN Bipolar Transistor
Allows current flow when low potential at
base
PNP Bipolar
Transistor
