basic electronics

1. REVIEW NOTES ON BASIC ELECTRONICS
Basic Electronics Technology
1. Electrical and electricity components, symbols 9 general, active and passive Symbols) 2. Summary of physics units, electrical characteristics Greek letters,
symbols, multiple and
sub units
3. Electron theory
4. Compilation of notes (Basic Electricity-Electronics)
5.Compilation of Notes (Basic Vacuum tubes, Diodes)
6. Sample problems (ohms law, Series, Circuits law, Parallel circuit law)
7. Facilitating Single Sided Printed Circuit Board
THE ELECTRON THEORY
All the effects of electricity take place because of the existing tiny particles called the electron No one has actually seen an electron except but the effects it
produces we call the laws governing its behaviour the electron theory. The theory is considered as the basis for the electrical and electronic equipment
design. It explains the chemical and physical action of electrons When electrons move things happen.
MATTER- Is composed of atoms of many differentiation, degrees of structural complexity and
weight
MOLECULE- The smallest particle into which an element or compound may be divided and still the chemical properties of the element is retained
MASS- The quantity of mater in a body. Mass is measure of inertia determines to acceleration
independently of the gravitational force.
ATOM- The smallest particle into which an element such as oxygen can be divided
NUCLEUS - The central part of the atom; it possesses a heavy positive change and contains nearly all the mass of the atom. The nucleus consists of proton
and neutron, together known as nucleons except hydrogen nucleus which consist only one proton.
NEUTRON- An elementary nuclear particle that has zero charge and mass number 1, making its mass approximately the same as that of a proton lonization is
produced by the products neutroncollision
PROTON- An elementary particle that has a heavy positively charge equal in magnitude to the negative charge of the electron.
ELECTRONS-An elementary negatively charged particles which are practically weightless, and circle around nucleus. It is also called negatron.

2. FREE ELECTRONS- Electrons that have left their orbit in an atom and are wandering/ move freely through a conducting material.
ELECRIC CURRENT-The directional movement of free electrons
POSITIVE CHARGE-A deficiency of electrons
Negative charge- An electric charge which has a surplus of electrons.
Ion - A charge atom or group of atom that becomes unbalanced. A negative ion has gained one or more extra electrons, whereas a positive lon has lost one or
more electron.
BASIC ELECTRICITY
ELECTRICITY-Is an invisible force that can produce heat, light, motion, and many other physical
effects. The is an attraction or repulsion between electric charges, more specifically, electricity can be explained in terms of electric charge, current, voltage
and resistance. A basic element of electricity is the electric charge. Current is the name given to the movement of charges. The study of electricity involves the
behaviour of charges, current and voltage with the component that make up the circuit.
CONDUCTORS -When electron moves easily from atom in a material with less opposition to current refer generally all materials are good conductors with
silver the best and copper second. I
NSULATOR-A material with atom in which the electrons tend to stay on their own orbit insulator because it cannot conduct electricity however, the insulator
is able to hold or store electricity better than conductors. An insulator can be useful when it is necessary to prevent flow.
CONDUCTORS- permit to flow changes in one or more directions
GOOD CONDUCTORS- Silver, copper, aluminium, zinc, brass and iron.
GOOD INSULATOR- Dry air, glass, ceramics mica, rubber, plastics and state.
ELECTRIC CHARGES:
The quantity of electric energy is measured by its own force of attraction and repulsion of two charges.
Negative charge- An excess of electrons
Positive charge- A lack of electrons
Repulsion charges- Like charges repel each other
Attraction charges- Unlike charges affect each other
Static electricity- Electric at rest
Friction Field- a field of force that surrounds a charge body

3. Electric field- A field of force surrounds a charged body.
Contact charges-Transfer of charges from one material to another by direct contract Induction charge Transfer of charge from one material to another
to another withou
Discharge of Electric charges
1. Contact Discharge- Charges can be neutralized by having the two material touch( contac together
2. Are discharge- Electrons crossing over from a negative charge to positive charge through an arc
MAGNETISM
A properly possessed by iron, steel and certain other magnetic materials, wherein these materials can produce or conduct magnetic line of force
capable of interacting with electric field or other magnetic fields
TYPES OF MAGNET
• Natural magnet or permanent magnet- A certain kind of material, which they
• originally found near the city of Magnesia in Asia Minor, has the power to attract and pick up bits of iron called magnetism. Temporary magnet
or electromagnet- A magnet consisting of a coil wound around a soft iron or steel core. The core is strongly magnetized when current flows
through the ceil and completely demagnetized when current is interrupted.
• Magnetic Poles -Points on a magnet where there is a strong concentration of magnetic magnet is allowed to swing freely, the North Polepoints
north and the South Pole points south.field. If the
Magnetic Materials- Materials that have magnetic groups of atom called domains. In unmagnified materials the strength of magnetic field.
TYPES OF ELECTRICITY
a. Static electricity- Electricity at rest: some materials which is easily build up static electricity are glass, amber hard rubber, wax, flannel, silk, rayon,
nylon, and fur
b. Dynamic electricity- Electricity at motion when the potential difference between two charged forces a third to move, the charge in motion is an
electric current. To produce current therefore, charge must be moved by potential.
PARTS OF ELECTRIC CIRCUIT
1. Source -Provide energy in order electric current moves. E.g. battery, generator
2. Conducting path- A wire, cable, or other body or medium that is suitable of carrying electric current.

4. 3. Load- A consumning device in an electric circuit
4. Switch-It isconsider as controlling device in an electric circuit
THE BIG THREE IN ELECTRICITY
Current (1)-A progressive movement of free electrons along a wire or other conductor. Current in measured in amperes (A)
Electromotive force or voltage (EMF, E. V)- It is an electric pressure that exist between two
points and capable of producing flow of current when a closed circuit is concerned between two points Voltage can be measure in volts (V)
Resistance Opposition offered by material to flow of current Resistance is measures in ohms
Solder and Flux
Solder and flux are used with a soldering iron to joint two materials. The flux dioxides the surface of the materials to solder can penetrate the pores of the
material. In Electronic work a rosin flux is always used Acid flux should never be used in electronic circuit as the acid will corrode the joint and build up an oxide
that will prevem electrical flow through the connections.
TYPE OF SOLDER GRADE:
• 60/40-60% tin and 40% lead (this is preferred in electronic works)
• 50/50-50% tin and 50% lead
• 40/60-40% tin and 60% lead
ADVANTAGES OF 60/40 SOLDER GRADE:
• It melts lowest temperature
• It hardens easily
• It is easier to do soldering job
FACTORS TO ACHIEVE GOOD SOLDERING (SOLDERING REQUIREMENTS)
1. Cleanliness it is the first to consider in soldering
2 Heat-varying amount of heat are required for different types of work
3. Flux and solder- Flux and solder come as one 60/40 rosin core solder is best electronic work
4. Good technique- Good soldering technique can be achieved by good practice
Don'ts in SOLDERING
1. Do not melt the solder in the soldering iron tool.
2. Do not keep the soldering tool on the joint tool long. As soon as the solder flows, remove the soldering tool and allow the joint to cool.

5. 3. Do not be tempted to wiggle the joint until it is completely cooled.
TYPICAL INFERIOR SOLDER CONNECTION:
1. Solder peaking-Churacterized by a sharp point of solder protruding from a connection Peaking is caused by the rapid removal of the heat before heat the
entire has had an opportunity to completely reach its soldering temperature.
2 In complete wetting- Occurs when portions of the soldered connections have not been allowed with solder and are completely visible. This may be the result
of both insufficiens heat and solder
3 Excessive solder- evident when the lead contour is not plainly visible.
4. Cold solder joint- An inferior connection easily detected by it by dull gray, grainy appearance, or as a cluster of solder that has not properly wetted all the
surfaces
5. Fractured joint- A joint in which a layer of flux residue is formed between the terminal pad and the solder since flux is an insulator, this condition could result
in electrical discontinuity between leads and the terminal pad. Rosin joints are the result of too short heating time 6. Fractured joint-characterized by the
appearance of minute cracks in the solder. The cracks
appear if the is moved before the solder has an opportunity of completely solidify
7. Porous joint- Characterized by pinhole imperfections visible in the surface of the solder
which is due to trapped gases causes by insufficient heating time, a period required to allow
volatizing flux to escape.
METHODS OF LEAD TERMINATION ON A PRINTED CIRCUIT BOARD:
a. Straight through
b. Full clinch
Semi-clinch
d. Spaded(side)
e. Spaded(front)
f Full cliched lead installed in eyelet
TOOLS REQUIRED IN SOLDERING:
• Soldering gun and iron
• Copper braid
• Lead bending tool Desoldering pump
• Heat sink to protect component Soldering wick to protect insulation
• Solvent- a cleaning fluid to remove oxide residue

6. Flux-a material that makes metals more amenable to being joined by soldering
BATTERIES:
A battery is a group of cell that generate electrie energy from their internal chemical action. The cell itself consists of two different conducting
materials as the electrode immersed in an electrolyte form of ions and the free electrons. As a result, the two electrodes have a difference of potential
that provides voltage output from the cell.
TWO TYPES OF CELL
Primary cell- a type of cell that cannot be recharged, After it has delivered tis rated capacity. the primary cell must be discarded. The reason is that the
internal chemical action cannot be restored
Secondary cell- a type of cell that can be recharged because the chemical action is reversible
EXAMPLE OF PRIMARY CELL
Carbon-Zinc
Zinc Chloride
Manganese dioxide
Mercury oxide
Silver-oxide Lithium cell
EXAMPLE OF SECONDARY CELL
Lead-acid
Nickel-cadmium
Nickel-iron(Edison cell)
Silver zinc
Silver-cadmium
MULTIMETER
All instruments used for industrial and laboratory testing have some methods of indicating the results of the tests as they are designed to perform The
most common indicating device is the scale. The scale can be graduated to indicate Volts, ohms, amperes, watts, decibel, gallons, miles or desired
quantity. Multifunction test common and most useful tool of the electronic trade. This instrument allows to make measurement of DC voltage, DC
current and resistance value
TYPES OF MULTI METER:
Analog multi-meter- The multi meter is usually having a moving meter Digital multi- meter type of meter that gradually replacing analog meter. They
are mechanically studier because they do not contain the delicate analog meter movement. They characterized by

7. high input impedance, better accuracy, and resolution, and resolution. and auto zero facilities
VOLTMETER-An instrument use to measured electrical current in the circuit.
AMMETER- An instrument use to measured electrical resistance in the circuit
OHMMETER- An instrument use to measure electrical resistance in the circuit. AUTORANGING A feature of digital multimeter that can shift its ranges
automatically without having to change ranges automatically without having to change ranges like in ranges of resistance
AUTOZERO- A feature of digital multimeterthat automatically sets the registered displays with zero value prior to measurement without having it
manually adjusted.
FUNDAMENTALS OF RADIO MECHANICS
RESISTANCE
Although it might seem that resistance has disadvantage in reducing the current in a circuit Actually resistors are probably the most common
components in electronic equipment.
http://en.wikipedia.org/wiki/Electronic_color_code
http://en wikipedia.org/wiki/Electronic color_code
Purpose of resistance:
• Limit the current flow
important Characteristics of RESISTOR:
• Resistance in ohms
Types of fixed resistor:
• Carbon composition
• Wire-wound resistor
• Produce voltage drop
• Power rating
• Carbon-film resistor
• Metal-film resistor
Types of variable resistor:
• Trimmer resistor
• Rheostat

9. Losses in a coil:
• Hysteresis loss -Energy loss due to the magnetic flux
• Eddy current loss Loss- due to the heat in the core Copper loss- Loss due to the resistance of the wire
Applications of inductors/coil
• Produce AC voltage drop
• Store energy
• Introduced time delay
• A low frequency to pass and reject all other frequency
• . Use as filter circuit
Air-core coil- a coil wound on a fiber, plastic or other non-magnetic form. with no iron in its vicinity
Bobbin- an insulated spool that is support for a coil
Core- Magnetic core- a quantity ferrous material place in a coli or transformer to provide a better path than air magnetic flix, thereby increasing the inductance of the coil and
increasing the coupling between the windings of a transformer
Ferromagnetic- a magnetic material that has a permeability considerably greater than permeability of a vacuum and which varies with the magnetic force .
Induced Current- a current produced in a conductor by time-varying electromagnetic field, induction heating
Induced Voltage-a voltage produced in a circuit by a change in the number of magnetic lines of
force passing through a coil in the circuit.
Inductor Connection
1. Series connection- Lt=L1+L2+LN
2. Parallel Connection LT=1/L1+L2+L3
Troubles in a coil:
• Open coil
• Shorted coil
• • Grounded coil
• Partially shorted
Inductance therefore, is the characteristics that oppose any change in current. This is the reason why an voltage is called a counter emf or back emf
TRANSFORMER
The transformer is an important application mutual inductance. A transformer has a three important parts namely, the primary winding, secondary winding and the core. The
purpose of the transformer is to transfer energy /power from the primary, where the generator is connected, to the secondary, where the induced secondary voltage can
produce current in the load resistance that is connected across L

10. Main parts of the transformer:
a. Primary winding- A coil winding connected to a voltage source
b. Secondary winding a coil winding connected to a load
c. Core- a magnetic core, quantity of ferrous material place in a coil or transformer to provide
better path of transfer of energy, thereby increasing the inductance of the transformer
Types of Transformer according to used:
1. Air core- A transformer that have two or more coils on a fiber or other non-magnetic form. usually designed for the used for R transformer
2. Powdered iron core transformer- A transformer that uses a powdered, compressed, and sintered magnetic material that has high resistivity. The high resistance
makes eddy current loses extremely low at high frequency.
3. Iron transformer- A transformer in which laminations of iron or other magnetic lines of force that link the transformer windings. Usually designed for very high
inductance such as power transformer, audio transformer, and audio type transformer.
Losses in transformer:
1. Core loss- The fact that the magnetic core can become warm or even hot, during operation (which some energy supplied to the coil is used up in the core as
heat) The two main
effects are eddy-current losses and hysteresis losses.
2. Eddy current loss- Losses due to the heat of the iron core (heat produce in the core considers as the wasted power
3. Hysteresis losses- Result from the additional power needed to reverse the magnetic field in magnetic materials with RF alternating current.
4. Cooper loss Loss due to the resistance of the coil
Classification of the transformer:
1. Isolation type- A transformer inserted into a system to separate one section of the system
from undesired influences of another section.
2. Auto type- transformer- A transformer that has one continuous tapped winding. Part of the winding serves as the primary, and all of its serves as the secondary,
vice versa.
Types of power transformer:
1. Step-up transformer- A type of transformer that its output voltage wind is much higher
than the input signal.
2. Step down transformer- A type of transformer that its output voltage/ winding is much
lower than the input signal.

11. Different types of transformer secondary winding:
1. Single Tapped. There is only single tap coil in the secondary winding
2. Center tapped- There is one common line with two hot lines in the secondary winding
3. Multi tapped-there is one only common line two hot line in the secondary winding
CAPACITANCE
One of the most used parts in radio and electronics is the capacitor, previously called a condenser A capacitor is has the ability to hold charge of electron. The number of electrons it
can store under a given pressure is a measure of a capacitance. Two separate metallic plates with non conducting substance sandwich between them is called dielectric, specifically
capacitanceis the ability of a dielectric to store electric charge. The unit in measuring of capacitanceis farad
Two types of capacitor:
1. Fixed capacitor- A type of capacitor that its capacitancecannot be varied
2. Variable capacitor- a type of capacitor that its capacitance can be varied manually.
Types of fixed capacitor
Polarized capacitor Non-polarized capacitor
Types of variable capacitor:
• Trimmer capacitor
• Variable capacitor
Types of a capacitor are named according to the electric material used:
Air capacitor, paper capacitor, mica capacitor, ceramic capacitor, electrolytic capacitor. tantalum capacitor, mylar capacitor, Sprague capacitor, oil capacitor
Application of capacitor:
• Store energy
• Produce AC voltage drop
• Use as a filter
• Introduce time delay
• Allow high frequency to pass and reject all ohms
Important characteristics of capacitors:
• Capacitancein farad
• Working voltage
Factors that affect the value of capacitance
• Area of the plates

12. Distance between the plates
Type of dielectric material used
Capacitor acquired new name when connected in the circuit:
Coupling capacitor De-coupling capacitor
Feedback capacitor
Bypass capacitor Filter capacitor
Capacitor troubles:
Shorted capacitor
Open capacitor
Leaky capacitor
Identifying the value
Printed
Stamped
Engraved
Coded-numerical code and color code
Charged- the quantity of energy stored in a capacitor, elementary particle or insulated objects Dielectric- A material that can serve as an insulator, it has poor
electric conductivity. A dielectric undergoes electric polarization when subjected to an electric field.
Polarization- a displacement of bound changes in a dielectric when placed in an electric field.
Trimmer capacitor- a variable semi-adjustable capacitor
Electrolytic capacitor- a capacitor consisting of two electrodes separated by an electrolyte
SEMI CONDUCTOR
A material whose resistivity is between that of insulators and conductors. The resistivity is often changed by light, heat, an electric field. Current flow is often
achieved by transfer of and transistors.
positive holes as well as by movement of electrons, Example include germanium, lead sulphide, lead telluride, selenium, silicon and carbon carbide Widely used in
diode, photocells, thermistors
Two types of semi-conductor
1. Intrinsic semi-conductor- A pure semi-conductor without any doping
2. Extrinsic semiconductor- A semi-conductor that undergoes doping process.
Intrinsic semi-conductor materials
An element which has only 4-valence electrons and non-metallic

13. Silicon (Si)- discovered in 1823 by J.J Berzelius, in which its element where recovered from silica rocks and sand with atomic no 14
Germanium(Ge) - discovered in 1886 by C.A. Winker which its elements where recovered from
the ashes of coal With atomic no 32
Extrinsic semi-conductor materials
When a pure semiconductor crystals (S1 or Ge) added to impurities, through doping process will
result to either N-type semi-conductor or P-Type semi-conductor
1. N-Type Semiconductor- Silicon/ Germanium added to impurities (pentavalent will result an N type- semiconductor.
PENATAVELNT IMPURITIES; Sometimes called as donor impurity
2. P-Type Semiconductor When a silicon Germanium added to impurities in
valentimpurities) will result a P type-semi conductor
CURRENT CARIERS IN A P-TYPE SEMICONDUCTOR
• Electrons-minority
• Holes-majority
Doping process- a process of adding an impurity atom to pure Ge or Si crystal section lattice/
CURRENT MOVEMENT IN SEMICONDUCTOR
When a P-type semiconductor put close together current moves with in the crystal lattice
1. Diffusion current (this will only occur when P and N-type are joined) electrons/holes current movement within the crystal lattice of doped semiconductor
without applying external force
2 Drift current- Electrons holes current movement in the crystal lattice of doped semi conductor without applying external force
JUNCTION DIODE/ PN DIODE
• Anode
• Cathode
Diode Is the simplest form solid state device. It has only two elements or electrode which is the anode and cathode. The anode is made up negative current
carriers or the P-type while the cathode is made up of negative current carriers of the N-Type, and separate by the junction
Bias applied to the junction diode or semi-conductor diode:
1. Forward bias- Offers low resistance, which the barrier voltage becomes neutral. The holes

14. and electrons are force to move the depletion zone, which cause the barrier to become
narrow. There is recombination of charges occurs at the junction
2. Reversed bias- The negative charges are attracted to the positive post of external charge and the positive charge, at this instance, the diode
is at reversed bias and no recombination of charges occurs at the junction, that will cause the depletion zone to become wider. It is bias that will
not allow current flow.
Basic classification of semi-conductor diode:
1. Signal diode- used in the circuit where power requirements are low and cannot withstand
heavy current. Use as detector in radio receivers known as crystal.
2. Power diode- used in the circunt where power requirements are much higher than signal diode and withstand heavy current such as rectifier
diode.
Simplest and the oldest known rectifier diode
Metallic or selenium rectifier
The arrow head represents the anode, whereas the bar signifies the cathode. The arrow and bar the standard symbols for semiconductor diode.
The arrow indicates the P side. The line or bar indicates the N side. In some cases, a dot or band at one end indicates cathode side. Sometimes,
a positive (+) mark at the cathode side shows that this is the terminal for the positive in the direction of conventional current flow in the diode
when it is forward biased Conventional current flow is from the positive terminal of the voltage source, through the load to the negative
terminal of the source.
Diode application
1. Power supply rectifier Converts AC inout from 60Hz power line to DC output.
2 Signal detector- The detector uses a diode to rectify a modulated signal in order to recover the modulated signal.
3. Digital logic gates- In these circuits, the diode functions as a switch. It is on when diode conducts and off without conduction.
SPECIAL PURPOSE DIODE
Rectifier diode- A diode that exhibits an asymmetrical voltage-current
Varactor diode- This is also varicap or capacitive diode. A two terminal semiconductor device in which is use is made of the fact that is
capacitance varies with the applied voltage.

15. Zener diode A two-layer device that above a certain reverse voltage (the
zener value), has a sudden rise in the current. If forward biased the diode is an ordinary rectifier but when reverse biased,
the diode exhibits the typical knee, or sharp break, in its current voltage graph. The voltage across the device remains
essentially constant For any further increase of reverse current, up to the allowable dissipation rating. The zener diode is
good voltage regulator, over voltage protector, voltage reference level, shifter etc. They name after CA Zener, who
analysed the voltage breakdown of insulators
Tunnel diode- A PN diode to which has been added a large amount of
impurity. The tunnel diode has high-speed charge movement and a negative-resistance region above a minimum level of
applied voltage. With the addition of suitable external circuits, it can be used as an oscillator or amplifier. Also called
ESAKI DIODE
Light emitting diode- PN junction that emits lights when hiased in the
forward direction. This light can be one of several visible color-red, yellow, green or it may be infrared and thus invisible
Electrically, a LED is similar to a conventional diode in that it has a relatively low forward voltage threshold
Schottky diodes- High frequency rectification; also referred to as hot
carrier diode.
Diode specifications (arranged by manufacturer)
1. Peak inverse Voltage (PIV)- this is the maximum voltage that can be applied to the diode in reverse direction without
destruction
2. Average rectified forward current- the current which the device is required to carry under normal operating range.
3. Peak rectified current the very maximum current, the device can conduct for a partial cycle of operation.
4. Surge current- the current that can conduct at maximum reverse voltage.
5. Reverse current- the maximum reverse current at maximum reverse voltage.

16. Troubles in semi-conductor diode:
a.Shorted diode
b. Open diode
c. Leaky diode