According to oxford dictionary Electronics is
"The branch of physics and technology concerned with the design of circuits using transistors and microchips, and with the behaviour and movement of electrons in a semiconductor, conductor, vacuum, or gas:"
The basic electronics covers following topics
1. Atoms
2. Electrical Charges
3. Current
4. Voltage
5. Resistance
6. Inductance
7. Capacitance
8. Magnetism
9. Capacitor
10. Power
11. Ohm law
12. resistors
ATOMS
usually Atom is considered as smallest particle of an element. It consist on
1. electron
2. proton
3. neutron
Electronics had negative charge on them which is equal to 1.6*10^-19 coulomb.
Proton had positive charge which is equal to the value of the charge as it is on electron.
Neutron are electrically neutral and does not pretend any electrical behaviour.
Number of electronics and protons in an atom is always equal which is also called the Atomic number.
While the number of proton decide the Atomic mass of atom in combination with protons. Means the number of protons+neutrans are known as Atomic Mass.
The protons and neutrons are present in the center of atoms forming what is called the nucleus and the electrons revolve around them.
ELECTRICAL CHARGES
It is important to remember that particles, which have same charge repel while unlike charges attract each other. Therefore a proton and electron will attract while a proton and proton will repel each other. In other words they will move away from each other. Electricity is the flow of electrons so it is necessary to measure the charge. The basic unit for measuring charge is the coulomb or the letter C.
1 columb charge is equal to the amount of 6.25*10^18 electrons.
CURRENT
Current is caused due to motion of electrical charge - the flow of electrons in a circuit is called current. Current is measured in AMPERES (AMPS, A or I).
Electric current is the amount of electrons, or charge, moving past a point every second.
Therefore amount of flow of current depends upon flow (speed) of electrons
I=Q/T
or
1 ampere = 1 coloumb / 1 sec
Therefore for every amp, there are 6.25x10^18 electrons moving through a point every second or A flow of electrons forced into motion by voltage is known as current.
VOLTAGE
Voltage is the electrical force or "pressure" that causes current to flow in a circuit. It is measured in VOLTS (V or E).
In other words, current can only flow only if voltage is applied between two terminals.
The difference between these two terminals is called the potential difference. The larger the potential difference, the larger the voltage.
Therefore, Voltage can be thought of as the measure of the pressure pushing the electrons.
One volt will cause 1 amp of current through 1 ohm of resistance.
RESISTANCE
The opposition in the way of flow of current is called Resistance. This is the property of every material whether it is conductor, semiconductor or insulator. This property classify the materials in three groups because in conductor resistance is very low while in semiconductor it is inbetween of conductor and insulator, while in insulator this resistance is too high.
Resistance is denoted by R
its unit is ohm and represent as sign of omega
different values resistances are available in different forms of resistors to get the right potential difference across each of them.
INDUCTANCE
Inductance can be defined as ability of the coil of wire to resist any change in electric current passing through the coil.
According to faradays law, the inductance L may be defined in terms of the emf generated to oppose a given change in the current.
The value of an inductance is directly proportional to the number of turns wound or used.
CAPACITANCE
The number of electrons that can be stored under a given electrical pressure (voltage) is called its capacitance or capacity. The property of capacitance is exhibited by capacitor. Basically, a capacitor consists of two metallic plates separated by a non-conducting substance between them.
In the circuit shown left when the switch is open the capacitor is not charged i.e. it does not contain any charges but when the switch is closed current starts to flow and capacitor gets charged. This process of charging takes place because the emf forces electrons into the top plate of the capacitor from the negative end of the battery and pulls others out of the bottom plate toward the positive end of the battery.
The unit uF stands for microfarad (one millionth) and pF stands for Pico-farad (one million, millionths). These are the two common values of capacitance you will encounter in electronics.
Time constant of capacitanceThe time required for a capacitor to get completely charged depends upon two factors:
1. The capacitance value
2. The resistance value.
The time constant of a resistance - capacitance circuit is:
T = R X CWhere T = time in seconds
where R = resistance in ohms
where C = capacitance in farads
MAGNETISM
Magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials.
Unlike electric charges (such as those observed when amber is rubbed against cloth), magnetic objects possessed two poles of opposite effect, denoted "north" and "south" after their self-orientation to the earth.
Materials like iron, steel, and the mineral lodestone are influenced by the presence of a magnetic field.
Basically, a magnetic field arises due to the moving electric charges.
There are various types of magnets depending upon Orientation of Electric Charges.
Depending upon domains Magnets are classified in three categories, which are as follows
1. Permanent Magnets
2. Temporary Magnets
3. Electro Magnets
1. Permanent Magnets
Permanent magnets are made from a ferromagnetic material, which at some point of time has been exposed, to a magnetic field. They are permanent in the sense that once they are magnetized, they retain a level of magnetism. Consider ferromagnetic material (one that can be magnetized without much effort), which can be made into a magnet by placing it in the centre of an electric coil or solenoid and passing a large current through the coil. If the material is magnetically `hard, it will retain its magnetism even when the current has been switched off. Permanent magnets are made from such hard materials as steel, nickel, and cobalt. Such magnetic alloys are used in electrical equipment and electronic devices
2. Temporary Magnets
Temporary magnets are those which act like a permanent magnet when they are within a strong magnetic field, but lose their magnetic property when the magnetic field disappears.
Examples: paperclips and nails and other soft iron items.
3. Electro Magnets
An electromagnet is a tightly wound helical coil of wire, usually with an iron core, which acts like a permanent magnet when current is flowing in the wire. The strength and polarity of the magnetic field produced by the electromagnet are adjustable by changing the magnitude of the current flowing through the wire and by changing the direction of the current flow.
CAPACITOR
A Capacitor is a passive electronic component that stores energy in the form of an electrostatic field.
Therefore Capacitors are used to store electric charge. Basically, a capacitor consists of two plates of a conducting material separated by a space filled by an insulator. The insulating layer is called the Dielectric of the capacitor.
Capacitance is directly proportional to the surface areas of the plates, and is inversely proportional to the plates separation.
The capacitor also functions as a filter, passing alternating current (AC), and blocking direct current (DC).
This symbol used to indicate a capacitor is -||-.
The fundamental property of a capacitor is that it can store charge and hence electric field energy. The capacitance C between two appropriate surfaces is defined by V=q\c where V is the potential difference between the surfaces and Q is the magnitude of the charge distributed on either surface
Capacitance is measured in units called
Farad: F
microfarad: µF (1 µF = 10-6 F)
nanofarad: nF (1 nF = 10-9 F)
picofarad: pF (1 pF = 10-12 F)
POWER
Power is defined as the amount of energy used or the amount of "work" done by a circuit.
Power is represented by the letter P.
The basic unit for measuring power is watts or the letter W.
P=EI
OHMS LAW
ohms law define the basic relationship of current, voltage, and resistance.
ohms law states that
"The amount of current flowing in a circuit is directly proportional to the electromotive forces impressed on the circuit and inversely proportional to the total resistance of the circuit."
According to the Ohms law, voltage equals current times resistance which is expressed in the following equation:
V=IR
where
V = voltage,
I = current
R = resistance
"The branch of physics and technology concerned with the design of circuits using transistors and microchips, and with the behaviour and movement of electrons in a semiconductor, conductor, vacuum, or gas:"
The basic electronics covers following topics
1. Atoms
2. Electrical Charges
3. Current
4. Voltage
5. Resistance
6. Inductance
7. Capacitance
8. Magnetism
9. Capacitor
10. Power
11. Ohm law
12. resistors
ATOMS
usually Atom is considered as smallest particle of an element. It consist on
1. electron
2. proton
3. neutron
Electronics had negative charge on them which is equal to 1.6*10^-19 coulomb.
Proton had positive charge which is equal to the value of the charge as it is on electron.
Neutron are electrically neutral and does not pretend any electrical behaviour.
Number of electronics and protons in an atom is always equal which is also called the Atomic number.
While the number of proton decide the Atomic mass of atom in combination with protons. Means the number of protons+neutrans are known as Atomic Mass.
The protons and neutrons are present in the center of atoms forming what is called the nucleus and the electrons revolve around them.
 |
ELECTRICAL CHARGES
It is important to remember that particles, which have same charge repel while unlike charges attract each other. Therefore a proton and electron will attract while a proton and proton will repel each other. In other words they will move away from each other. Electricity is the flow of electrons so it is necessary to measure the charge. The basic unit for measuring charge is the coulomb or the letter C.
1 columb charge is equal to the amount of 6.25*10^18 electrons.
CURRENT
Current is caused due to motion of electrical charge - the flow of electrons in a circuit is called current. Current is measured in AMPERES (AMPS, A or I).
Electric current is the amount of electrons, or charge, moving past a point every second.
Therefore amount of flow of current depends upon flow (speed) of electrons
I=Q/T
or
1 ampere = 1 coloumb / 1 sec
Therefore for every amp, there are 6.25x10^18 electrons moving through a point every second or A flow of electrons forced into motion by voltage is known as current.
VOLTAGE
Voltage is the electrical force or "pressure" that causes current to flow in a circuit. It is measured in VOLTS (V or E).
In other words, current can only flow only if voltage is applied between two terminals.
The difference between these two terminals is called the potential difference. The larger the potential difference, the larger the voltage.
Therefore, Voltage can be thought of as the measure of the pressure pushing the electrons.
One volt will cause 1 amp of current through 1 ohm of resistance.
RESISTANCE
The opposition in the way of flow of current is called Resistance. This is the property of every material whether it is conductor, semiconductor or insulator. This property classify the materials in three groups because in conductor resistance is very low while in semiconductor it is inbetween of conductor and insulator, while in insulator this resistance is too high.
Resistance is denoted by R
its unit is ohm and represent as sign of omega
different values resistances are available in different forms of resistors to get the right potential difference across each of them.
INDUCTANCE
Inductance can be defined as ability of the coil of wire to resist any change in electric current passing through the coil.
According to faradays law, the inductance L may be defined in terms of the emf generated to oppose a given change in the current.
The value of an inductance is directly proportional to the number of turns wound or used.
CAPACITANCE
The number of electrons that can be stored under a given electrical pressure (voltage) is called its capacitance or capacity. The property of capacitance is exhibited by capacitor. Basically, a capacitor consists of two metallic plates separated by a non-conducting substance between them.
In the circuit shown left when the switch is open the capacitor is not charged i.e. it does not contain any charges but when the switch is closed current starts to flow and capacitor gets charged. This process of charging takes place because the emf forces electrons into the top plate of the capacitor from the negative end of the battery and pulls others out of the bottom plate toward the positive end of the battery.
The unit uF stands for microfarad (one millionth) and pF stands for Pico-farad (one million, millionths). These are the two common values of capacitance you will encounter in electronics.
Time constant of capacitanceThe time required for a capacitor to get completely charged depends upon two factors:
1. The capacitance value
2. The resistance value.
The time constant of a resistance - capacitance circuit is:
T = R X CWhere T = time in seconds
where R = resistance in ohms
where C = capacitance in farads
MAGNETISM
Magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials.
Unlike electric charges (such as those observed when amber is rubbed against cloth), magnetic objects possessed two poles of opposite effect, denoted "north" and "south" after their self-orientation to the earth.
Materials like iron, steel, and the mineral lodestone are influenced by the presence of a magnetic field.
Basically, a magnetic field arises due to the moving electric charges.
There are various types of magnets depending upon Orientation of Electric Charges.
- When a magnet is suspended
freely, one side points North. This is called the North Pole of the
magnet. The other side points South, and is called the South Pole of the
magnet.
A magnetic compass is used for finding north and South Pole.
- A magnet is surrounded by
an invisible force field. Electric coils, currents in wires, and
permanent magnets are all sources of magnetic field. Moving charged
particles produces magnetic fields. In case of electromagnets, electron
flow through a coil of wire connected to a battery; in permanent
magnets, spinning electrons within the atoms produces the field. Lines
of magnetic force can be seen around a magnet by sprinkling iron filings
on to a sheet above it and tapping the sheet. The strength of the
magnetic force is strongest close to the poles and gets weaker as you
move away from the poles.
Normally the electrons are paired up and they cancel each others field; but in iron, some of the electrons are unpaired. Their spins tend to line up together, creating tiny pockets of magnetism called magnetic In the atoms of magnetic metals, the electrons spinning around the nucleus create a small magnetic field. domains.
Depending upon domains Magnets are classified in three categories, which are as follows
1. Permanent Magnets
2. Temporary Magnets
3. Electro Magnets
1. Permanent Magnets
Permanent magnets are made from a ferromagnetic material, which at some point of time has been exposed, to a magnetic field. They are permanent in the sense that once they are magnetized, they retain a level of magnetism. Consider ferromagnetic material (one that can be magnetized without much effort), which can be made into a magnet by placing it in the centre of an electric coil or solenoid and passing a large current through the coil. If the material is magnetically `hard, it will retain its magnetism even when the current has been switched off. Permanent magnets are made from such hard materials as steel, nickel, and cobalt. Such magnetic alloys are used in electrical equipment and electronic devices
2. Temporary Magnets
Temporary magnets are those which act like a permanent magnet when they are within a strong magnetic field, but lose their magnetic property when the magnetic field disappears.
Examples: paperclips and nails and other soft iron items.
3. Electro Magnets
An electromagnet is a tightly wound helical coil of wire, usually with an iron core, which acts like a permanent magnet when current is flowing in the wire. The strength and polarity of the magnetic field produced by the electromagnet are adjustable by changing the magnitude of the current flowing through the wire and by changing the direction of the current flow.
CAPACITOR
A Capacitor is a passive electronic component that stores energy in the form of an electrostatic field.
Therefore Capacitors are used to store electric charge. Basically, a capacitor consists of two plates of a conducting material separated by a space filled by an insulator. The insulating layer is called the Dielectric of the capacitor.
Capacitance is directly proportional to the surface areas of the plates, and is inversely proportional to the plates separation.
The capacitor also functions as a filter, passing alternating current (AC), and blocking direct current (DC).
This symbol used to indicate a capacitor is -||-.
The fundamental property of a capacitor is that it can store charge and hence electric field energy. The capacitance C between two appropriate surfaces is defined by V=q\c where V is the potential difference between the surfaces and Q is the magnitude of the charge distributed on either surface
Capacitance is measured in units called
Farad: F
microfarad: µF (1 µF = 10-6 F)
nanofarad: nF (1 nF = 10-9 F)
picofarad: pF (1 pF = 10-12 F)
- Time constant of capacitance The time required for a capacitor to get charged is proportional to the capacitance value and the resistance value.
The time constant of a resistance - capacitance circuit is:
T = R X C Where T = time in seconds
Where R = resistance in ohms
Where C = capacitance in farads
Capacitors in series and parallel When Capacitors are connected in parallel say C1,C2,C3,…….
Add capacitor values together as C1 + C2 + C3 + ..... to get net capacitor value
When capacitors are connected in series.
The net value is calculated in following manner
1 / (1 / C1 + 1 / C2 + 1 / C3 + .....)
POWER
Power is defined as the amount of energy used or the amount of "work" done by a circuit.
Power is represented by the letter P.
The basic unit for measuring power is watts or the letter W.
P=EI
OHMS LAW
ohms law define the basic relationship of current, voltage, and resistance.
ohms law states that
"The amount of current flowing in a circuit is directly proportional to the electromotive forces impressed on the circuit and inversely proportional to the total resistance of the circuit."
According to the Ohms law, voltage equals current times resistance which is expressed in the following equation:
V=IR
where
V = voltage,
I = current
R = resistance
| RESISTORS | ||||||||||||||||||||||||||||||
 The resistors function is to oppose the flow of electric current. The most common schematic symbol for a resistor is a zigzag line shown in above diagram.  An alternative schematic symbol for a resistor is a small and rectangular in shapeResistors are also classified according to the material from which they are made. The typical resistor is made of either carbon film or metal film. The value of resistor is determined by its colour.
While selecting a resistor it is important to take value of tolerance and electric power rating of the resistor into consideration along with resistance value of the resistor. The tolerance of a resistor denotes how close it is to the actual rated resistance value. For example, a ±1% tolerance would indicate a resistor that is within ±1% of the specified resistance value, and the power rating indicates how much power the resistor can safely tolerate. The maximum rated power of the resistor is specified in Watts.
There are two kinds of resistors namely fixed resistors and the variable resistors.
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Variable ResistorsThere
are two general ways in which variable resistors are used. Adjustment
of one of the resistor is such that its value can be easily changed,
like the volume adjustment of Radio while adjustment of Semi-fixed
resistors are done to compensate for the inaccuracies in the resistors,
and to fine-tune a circuit. The rotation angle of the variable resistor
is usually about 300 degrees. At certain situation, variable resistors
must be rotated according to get the whole range of resistance they
offer. This allows for very precise adjustments of their value. These
are called "Potentiometers" or "Trimmer Potentiometers."