MODULE 1: Intro and Fundamentals of vacuum tubes Flashcards
It is the technology based on the behavior and properties and controls of electrons
electronics
is the premier nanoprocessing and nanotechnology journal focusing on fabrication of electrnic, photonic, bielectronic, electro mechanic and fluidic devices
mircoelectronics
a branch of electronics in which electronic instruments and equipment are used for such medical application
biomedical electronics
the process of analyzing and modifying
a signal to optimize or improve its efficiency or performance. It involves
applying various mathematical and computational algorithms to analog and
digital signals to produce a signal that’s of higher quality than the
original signal.
DIGITAL SIGNAL PROCESSING
is the field of electrical engineering, and now to some
extent computer engineering and information technology, which deals
with radio and television broadcasting.
BROADCAST ENGINEERING
involves both
the studio end and the transmitter end (the entire airchain), as well as remote
broadcasts.
BROADCAST ENGINEERING
is the branch
of engineering dealing with sound and vibration. It is the application
of acoustics, the science of sound and vibration, in technology.
ACOUSTICAL ENGINEERING OR ACOUSTIC ENGG
____________ engineers are typically concerned with the design, analysis and control of
sound.
ACOUSTIC ENGINEER
helps to produce a recording or a performance, editing and
adjusting sound tracks using equalization and audio effects, mixing,
reproduction, and reinforcement of sound.
AUDIO OR VOCAL OR RECORDING ENGG
is a technology professional who has the necessary skills to
plan, implement and oversee the computer networks that support in-house
voice, data, video and wireless network services.
NETWORK ENGINEER
is a discipline founded around the
exchange of information across channels via wired or wireless means. It brings
together all of the elements of electrical engineering, including
computer engineering and system engineering, to create and
improve telecommunication systems.
TELECOMMUNICATIONS ENGINEERING
A field of electronics that prepares individuals to apply technical knowledge
and skills to assemble, install, operate, maintain, and repair
electrical/electronic equipment used in industry and manufacturing.
INDUSTRIAL ELECTRONICS
is a multidisciplinary field of science that includes a
combination of mechanical engineering, electronics, computer engineering,
telecommunications engineering, systems engineering and control
engineering.
MECHATRONICS
A
typical ___________ system picks up signals from the environment, processes
them to generate output signals, transforming them for example into forces,
motions and actions.
MECHATRONIC
is a branch of engineering that involves the conception, design,
manufacture, and operation of robots.
ROBOTCS
Give Asimov’s three laws of robotics
- Robots must never harm human beings.
- Robots must follow instructions from humans without violating rule 1.
- Robots must protect themselves without violating the other rules.
It is a basic electronic element that is available
in a discrete form that has two or more
electrical terminals.
ELECTRONIC COMPONENT
What are the two classification of electronic components
Passive and active devices
These are components incapable of controlling current
by means of another electrical signal.
PASSIVE DEVICES
Give examples of passive devices (prcitd)
Resistors, capacitors, inductors, transformers, and even
diodes
any type of circuit component with
the ability to electrically control electron flow
(electricity controlling electricity).
ACTIVE DEVICES
GIVE EXAMPLES OF ACTIVE DEVICES
vacuum
tubes, transistors, silicon-controlled rectifiers (SCRs),
and TRIACs.
Devices utilizing a static voltage as the controlling
signal are called _________
voltage-controlled devices.
Devices working on the principle of one current
controlling another current are known AS _____
current controlled
devices.
Derived from the Greek word “atomos”,
meaning “indivisible”
ATOM
It is the tiny basic building block of all
matters.
Electronics
ATOM
Proposed by Sir Joseph John Thomson in 1904
THOMSON MODEL OR PLUM PUDDING
J. J. Thomson considered that the structure of an
atom is something like a _____, so that his
atomic model is sometimes called the _______
RAISIN, RAISIN BREAD MODEL
He assumed that the basic body of an atom is a
spherical object containing electrons confined in
homogeneous jellylike but relatively massive
positive charge distribution.
JJ THOMSON
Proposed by Ernest Rutherford in 1911 (GIVE 2 TERMS)
RUTHERFORD MODEL OR PLANETARY MODEL
electric charge in an atom is not distributed over
the whole area of the atom but concentrates in a
small area, he called the nucleus. (WHAT MODEL)
PLANETARY MODEL
He published his atomic theory describing the
atom as having a central positive nucleus
surrounded by negative orbiting electrons.
RUTHERFORD
This model suggested that most of the mass of the
atom was contained in the small nucleus, and that
the rest of the atom was mostly empty space.
PLANETARY OR RUTHERFORD MODEL
Proposed by Niels Bohr in 1913
• Modification of the Rutherford Model
• Each orbit has a corresponding amount of energy
Electronics Engineering
BOHR MODEL
depicts the atom as a small,
positively charged nucleus surrounded by
electrons that travel in circular orbits around the
nucleus—similar in structure to the solar system,
but with electrostatic forces providing attraction,
rather than gravity.
BOHR MODEL
The _______ model is a quantum-physics–based
modification of the Rutherford model.
BOHR
In Bohr’s model, energy levels are _________.
Only specific discrete energy levels are possible.
QUANTIZED
When electrons orbit the nucleus in more distant
orbits, they have ______ total energy.
MORE
The lowest energy level is the _____ state, and
higher energy levels are the first, second, etc.,
______ states.
GROUND, EXCITED
There are fractional energy levels. TRUE OR FALSE
FALSE
Electrons can jump up or down between energy
levels, but can have energy values between
the allowed energy levels. TRUE OR FALSE
FALSE (CAN HAVE)
Discovered by Sir Joseph John Thomson in April
30, 1897
ELECTRONS
Discovered by Ernest Rutherford in 1919
PROTONS
Discovered by Sir James Chadwick in 1932
NEUTRON
Has a mass approximately equal (but slightly
heavier) to that of a proton but has no electric
charge
NEUTRON
MP = \_\_\_\_ME MN = \_\_\_\_\_ ME
1837,1839
Equal to the number of protons in the nucleus, which
is the same as the number of electrons in an
electrically balanced (neutral) atom
ATOMIC NUMBER
Equal to the sum of the number of protons and
neutrons of an atom
ATOMIC MASS
Each orbital shell must be filled with a
maximum number of 2n2 electrons
2N^2
Loose electrons found in the outermost orbit of an
atom
VALENCE ELECTRONS
Indicate how easily the atom can gain or lose
electrons
VALENCE ELECTRONS
A substance, body or material which has more
electrons that are free to move.
CONDUCTOR
the released
electron dislodged from its
original shell due to
absorption of energy
Free Electron
the term used to refer to the vacancy left by
free electron when it departs from its original shell;
it usually behaves like a positive charge since it
can attract and capture electron in the immediate
vicinity
HOLE
A substance, body or material which has a
characteristic that is extremely opposite to
that of a conductor with more than four
valence electrons but ideally, it has ______valence
electrons.
INSULATOR, 8
the term for eight valence
electrons because they are tightly held by the atoms
Bound Electrons
A substance, body or material which has a
characteristic in between a conductor and
insulator, and has four valence electrons.
Semiconductor
A semiconductor in its pure (intrinsic) state is
neither a good conductor nor a good insulator. T OR F
TRUE
The most common single-element
semiconductors are _______
silicon, germanium and
carbon.
Compound semiconductors such as
_______are also commonly used.
gallium arsenide
Threshold Voltage OF SILICON
0.7v
Threshold Voltage OF germanium
0.3v
The farther the electron is from the nucleus, the
_____is the energy state, and
higher
any electron that
has left its parent atom has a_____energy state
than any electron in the atomic structure.
higher
It is the energy difference between the
conduction band and valence band.
ENERGY GAP
It is the energy required to move or transfer a
valence electron at the valence band to the
conduction band
ENERGY GAP
EG OF INSULATOR
Eg >5eV
EG OF CONDUCTOR
Eg = 0 V
Eg of silicon
Eg = 1.1 eV
Eg of Ge
Eg = 0.67 eV
Eg of GaAs
Eg = 1.43 eV
Also known as electrical potential difference, electromotive force (emf) or electric pressure
VOLTAGE
VOLTAGE IS NAMED AFTER ___
ALESSANDRO VOLTA
It is defined as the quantitative expression of the
potential difference in charge between two points in
an electric field.
VOLTAGE
The greater the voltage, the LOWER the flow of
electric current through a conducting or
semiconducting medium for a given resistance to the
flow.
Electronics
FALSE
CURRENT IS NAMED AFTER ____
ANDRE MARIE AMPERE
It is the flow of electric charges.
CURRENT
It is defined as the quantity of charge carriers
that pass a fixed point per unit of time.
CURRENT
RESISTANCE IS NAMED AFTER ____
GEORGE SIMON OHM
It is the quantitative expression of the opposition to
the passage of an electric current through a conductor.
RESISTANCE
It states that the current through a conductor between
two points is directly proportional to the potential
difference across the two points, and inversely
proportional to the resistance through it.
Ohm’s LAW
Also colloquially known as Wattage
POWER
It is the rate at which electric energy is transferred by
an electric circuit.
POWER
The real measure of electric shock’s
intensity lies in the amount of ______
forced through the body, and not the
voltage.
CURRENT
Any amount of current over ____
milliamperes is
capable of producing painful
to severe shock.
10
Currents between ____mA and
___ mA ) are
LETHAL!
Electronics
100, 200
The liberation of electrons from an electrode into
the surrounding space, usually under the
influence of heat, light, or a high electric field.
Electronic Emission
It is the force that restrains the emission of
electrons.
Potential Barrier
It is the process of emitting electrons by supplying
heat energy.
Thermionic Emission
It is the process by which charge carriers, such as
electrons, move over a surface or over a potentialenergy
barrier by applying thermal energy in order
to overcome the binding potential of the material.
Thermionic Emission
In ________, electrons gain sufficient
energy to escape from the metal electrode and
become free electrons.
Electronics
Thermionic Emission
It is the process of emitting electrons wherein the
energy of light radiation falling upon the metal
surface is transferred to the free electrons within the
metal and speeds up sufficiently to enable them to
leave the surface.
Photoelectric Emission
In Photoelectric Emission, the emission of electrons is dependent on the
_______ striking the metal surface.
Electronics
intensity of light
A strong electric field set up by a high positive
voltage pulls the electrons out of the cathode surface.
Field Emission
When a high-speed electron strikes a metallic
surface they give up their kinetic energy to the
electrons and atoms which they strike.
Secondary Emission
Bombarding electrons collide with the electrons in
the metal consequently ejecting them out of the
surface. what type of emission is this?
Secondary Emission
It is also known as “electron
tube”.
VACUUM TUBE
Vacuum tube is an electronic device which
consists of an ______
structure enclosed in a _______ or _____ container that is
evacuated.
ELECTRODE
GLASS OR METAL
It is the flow of current through a
laboratory vacuum, between two metal
wires, one of which is heated.
EDISON EFFECT
The current flows only when the heated
wire is______ because it is carried
by free electrons released from the wire by
its heat.
more negative,
It is the principle behind vacuum tubes.
EDISON EFFECT
VACUUM TUBES CONTAINS TWO PARTS. IDENTIFY THE PARTS
CATHODE AND ANODE
the electrode that emits electrons
CATHODE
the electrode that collects the emitted electrons
ANODE/PLATE
has a positive potential applied with respect to the
cathode, so that the emitted electrons are attracted to
provide plate current
ANODE/PLATE
After the tube is assembled, \_\_\_\_\_ is exhausted from the envelope (vacuum).
AIR
Among the methods of electron emission,
______ emission is most commonly used in
vacuum tubes.
THERMINOC
MENTION THE 4 TYPES OF EMISSION
THERMIONIC, PHOTOELECTRIC, FIELD, SECONDARY
electric current is applied to a
filament wire, which also serves as the cathode; the
emitter is usually made of either tungsten or oxidecoated
material
DIRECT HEATING
the cathode is electrically
heated by a separate heater element located inside it
IDIRECT HEATING
changes its ac input to pulsating dc output
Rectifier
generates ac output from its power supply,
without any ac input signal
Oscillator
amplifies its input signal
Amplifier
give the uses of vacuum tubes
amplifier, rectifier, oscillator
invented by J.A. Fleming in 1904
DIODE
DIODE IS ALSO CALLED AS
Fleming Valve or Thermionic
Valve
simplest type of vacuum tube that consists
of two metal electrodes: the plate/anode and
the cathode
DIODE
Electrons are emitted from the cathode by
supplying heat either directly or indirectly. WHAT TYPE OR VAUUM TUBE
DIODE
IN A DIODE, During the heating process, a cloud of free
electrons called ______ is formed near
the cathode.
SPACE CHARGE
in forward biased, the vacuum tube diode acts like
a ____ switch or a ____ circuit.
CLOSED, SHORT
if the voltage at the plate is made
negative with respect to the cathode, free
electrons are pushed back to the cathode
and no current flows, like an open-circuit.
REVERSED BIASED
By applying a positive voltage to the plate
with respect to the cathode, the free electrons
repelled by the cathode are attracted towards
the plate.
FORWARD BIASED
Due to the nature of the vacuum tube diode
to conduct current in a particular direction
and act as an open circuit when impressed
with a voltage of the other direction, it is
used as a ____
rectifier
It is the minimum point at which
the tube no longer operates.
Below, this value, no plate current
flows.
cutoff point
it is the maximum point wherein
raising the plate voltage no longer
increases the plate current
Saturation Point
It was invented by Dr. Lee De Forest in 1906
triode
another term for triode
De Forest Tube.
It is a device that provides amplification and it is
considered as the first amplifier.
triode
It is similar in construction to the vacuum tube
diode except that a third electrode, called _______, is placed between the cathode and the plate.
triode, control grid
current in the _____
could be controlled by adjusting the grid potential
with respect to the cathode.
triode
This device was found to be capable of amplifying
small signal voltages
triode
The potential applied to the control grid is
usually a ______ voltage with respect
to the cathode.
small negative
The grid voltage is usually made ____ so
that it cannot attract electrons.
negative
The function of the _______ is not to provide
current but to have its voltage control the plate
current.
CONTROL GRID
number of electrons at the grid is equal to the number of positive charges at the plate, hence \_\_\_\_\_\_\_\_
NO CURRENT WILL FLOW
Less negative grid voltage ______ the plate
current.
increases
More negative grid voltage ______the plate
current.
decreases
If the grid voltage is made negative enough, there
WILL BE OR NO plate current even with the plate positive.
NO PLATE CURRENT
The ability of the ______ to vary the plate
current makes the triode amplify small AC signal.
CONTROL GRID
Any two conductors in space have a capacitance
between them. Thus, a capacitance exists between
each pair of electrodes in a vacuum tube.
INTERELECTRODE CAPACITANCES
They are also called stray or parasitic
capacitances.
INTERELECTRODE CAPACITANCES
The addition of another grid, called _______,
reduces the grid-to-plate stray capacitance.
screen grid
The screen grid is placed between the ______and the ____and is close to the_____
control grid, plate, plate
It is not used to control the plate current but
has a steady positive dc voltage to help
accelerate electrons to be collected by the
plate.
control grid
______ emission occurs in tetrode
Secondary
It is simply a vacuum tube tetrode with an additional electrode called the \_\_\_\_\_\_\_ inserted between the screen grid and the plate to overcome the undesirable effects of secondary emission.
pentode, suppressor grid
Usually, the suppressor grid is connected
internally to the _____
cathode
first electronic generalpurpose
computer
Electronic Numerical
Integrator and Computer
Disadvantages of Vacuum Tubes
Bulky
- High power consumption
- High operating voltages required
- Less suitable for portable products
