2.  Electronics is a much more subtle kind of
electricity in which tiny electric currents (and, in
theory, single electrons) are carefully directed
around much more complex circuits to process
signals (such as those that carry
radio and television programs) or store and
process information. Think of something like
a microwave oven and it's easy to see the
difference between ordinary electricity and
electronics. In a microwave, electricity provides
the power that generates high-energy waves that
cook your food; electronics controls the electrical
circuit that does the cooking.

3.  SMT or surface mount technology is a method for
producing electronic circuits in which the components are
placed directly onto the surface of a PCB.
 An electronic device so made is called surface mounted
device. It has replaced through hole technology. It was
earlier called as planar mounting. Much of the pioneering
work was by IBM.
 They are known by various names depending upon the
components used, techniques, and machine used in
manufacturing.
 Some examples are:-
SMD:-surface mount device
SMT:-surface mount technology
SMA:-surface mount assembly
SMC:-surface mount components

5.  Through-hole mounting is the process by
which component leads are placed into drilled
holes on a bare PCB. The process was
standard practice until the rise of surface
mount technology (SMT) in the 1980s, at
which time it was expected to completely
phase out through-hole. Yet, despite a severe
drop in popularity over the years, through-
hole technology has proven resilient in the
age of SMT, offering a number of advantages
and niche applications: namely, reliability.

6. Through Hole Technology

7.  A power supply is an electronic device that supplies
electric energy to an electrical load.
 The primary function of the power supply is to
convert one form of electrical energy to other and
as a result they are also termed as electric power
converters.
 Examples are in desktop and other electronic
components.
 They are categorized into various ways including by
functional feature.

8.  Low / Negligible drop over long distances
 Non-Lethal
 Efficient Power transfer i.e. Low power wastage
 Ability to connect Sources and Sinks arbitrarily
 Ability to Step-up or Step-down as per
requirement with simple equipment

9.  Regulated power supply is the one that maintains
constant output voltage or current despite variations
in load current or input voltage.
 Unregulated power supplies on the other hand output
may vary with changes in the input voltage or load
current changes.
 Adjustable power supplies allows the output voltage
or current to be programmed by mechanical controls
or by means of control input, or both.
 Adjustable regulated power supply is one that is both
adjustable as well as regulated.
 Isolated power supply has a power output that is
electrically independent of its power input.

10.  DC POWER SUPPLY
A dc power supply generally is the one that
supplies voltage of fixed polarity to its load.
Depending upon its design a DC power supply
may be powered from a dc source or ac
source.

11.  AC TO DC POWER SUPPLY
Usually some dc power supplies uses ac mains electricity
as an energy sources. Such power supplies will
sometimes employ a transformer to convert input voltage
to higher or lower ac voltage.
A rectifier is used to convert transformer output voltage to
varying dc voltage which in turn is passed through an
electronic filter to convert unregulated dc voltage.
This filter removes most of the ac voltage variations but
not all the remaining voltage variations are known as
RIPPLE.
In some applications high ripple is tolerated and therefore
no filtering is required.

13. It is a passive two terminal electrical components that
implements electrical resistance
It is used to reduce the current flow and at the same
time may act to lower voltage levels within circuits.
In electronics it is used to lower current flow and to
adjust signal levels.
High power resistors is used for generating enough
heat to dissipate many watts of electrical power as
heat that can be used for motor controls.

14. Inside of a Resistor

15. Resistors colour code chart

16. Formulae of a Resistor

18.  TWO TYPES OF RESISTORS
FIXED
RESISTORS
VARIABLE
RESISTORS
They have resistance
that only change with temperature
They are used to
adjust circuit elements
Or as sensing devices.

19.  Carbon Composition Resistor – Made of
carbon dust or graphite paste, low wattage
values
 Film or Cermet Resistor – Made from
conductive metal oxide paste, very low
wattage values
 Wire-wound Resistor – Metallic bodies for
heat sink mounting, very high wattage ratings
 Semiconductor Resistor – High
frequency/precision surface mount thin film
technology

20. Carbon composition
Printed carbon composition
Thick film resistors
Thin film resistors

21.  Adjustable resistors:-A resistor may have one or more
fixed tapping points so that the resistance can be changed by
moving the connecting wires to different elements. This will
allow a larger or smaller part of resistance to be used. A
rheostat is a perfect example of this.
 POTENTIOMETERS:-A potentiometer or pot is a three
terminal resistor with a continuously adjustable tapping point
controlled by a rotation shaft or knob or by a linear slider. It
is called potentiometer because it can be connected as an
adjustable voltage divider to provide a variable potential at
the terminal connected to the tapping point. High resolution
and low resolution are its types.

22. Rheostat
Potentiometer

23.  The behaviour of an ideal resistor is given by
V=I.R.
 It states that voltage (V) across resistor is
proportional to the current(I),where the
constant of proportionality is resistance(R).
 The ohm is the S.I unit of resistance named
after George Simon Ohm.
 we define resistance more precisely as the
voltage in volts required to make a current of
1 amp flow through a circuit. If it takes 500
volts to make 1 amp flow, the resistance is
500 ohms (written 500 Ω).

24.  IN SERIES, so that the same current flows through
all the components but a different potential
difference (voltage) can exist across each one.
 IN PARALLEL, so that the same potential difference
(voltage) exists across all the components but each
component may carry a different current.
 The total resistance of resistors connected in series is
the sum of individual resistance values i.e.
Req=R1+R2+___________+Rn
 The total resistance of resistors connected in parallel
is the reciprocal of the individual resistors.
i.e.
1/Req=1/R1+1/R2+___________+1/Rn

25.  The power(watts) consumed by a resistor of resistance
R(ohms) is calculated as:-
p=(I)^2R=IV=(V)^2/R
Where V is the voltage across the resistor and I is the current
flowing through it. Using ohms law other two can be derived.
 The amount of heat that a resistive element can
dissipate for an indefinite period of time without
degrading its performance.
 If the average power dissipated by a resistor is more than its
power rating damage to resistor may occur, permanently
altering to its resistance. Excess power dissipation may burn
the circuit board or adjacent components and even can cause
fire.

26. A simple triangle rule for calculating power
Dissipation

27. Various types of resistors
Power resistors
Smd resistors in various sizes
Through hole resistors

28.  The measurement is usually done with ohmmeter
which may be one of the function of millimetre.
Generally there are two probes on the ends of test
leads connect to the resistor.
 For measuring low value resistors such as
fractional ohm resistors with acceptable accuracy
requires four terminal connections. One pair of
terminal applies a known calibrated current to the
resistor while the other pair senses the voltage
drop across it.

29.  Just like the Resistor, the Capacitor, sometimes referred to as
a Condenser, is a simple passive device that is used to “store
electricity”. The capacitor is a component which has the ability or
“capacity” to store energy in the form of an electrical charge
producing a potential difference (Static Voltage) across its plates,
much like a small rechargeable battery.
 When there is potential difference across the conductors an
electric field develops across the dielectric, causing positive
charge to accumulate on one side of the plate and negative
charge to accumulate on other side of the plate. If a battery is
attached to the capacitor for a sufficient amount of time then
there will be no flow of current through the capacitor however
this can be stopped if voltage is applied across the leads of the
capacitor, a displacement current can flow.
 SI UNIT OF CAPACITOR IS FARAD WHICH IS EQUAL TO ONE
COULOMB PER VOLT(1 C/V).
 Typical capacitor range from 1pF to 1mF.

30. Pieter van invented a capacitor which was named Leyden jar and found that
Touching the wire resulted in a powerful spark much more painful than the
Electrostatic machine.
Leyden jar

31.  Time delay:-It takes time to charge the capacitor and
thus gives some measurement of time ex:- Traffic
light control , Light turn off, delays etc.
 Power smoothing:-Since we use ac supply or our
mains power is ac there are many moments when
supplied volts are zero without capacitors the system
would stop 100 times every second.
 Isolation of D.C. Voltage.
 It protects against surges and spikes. The excess
power flows into the capacitor which temporarily
absorbs the power without giving a massive surge
EMF into the circuit.
 Serves as a tone control by lessening the response of
a circuit to high frequency waves.

32. The schematic symbol for a capacitor actually closely resembles how it’s
made. A capacitor is created out of two metal plates and an insulating
material called a dielectric. The metal plates are placed very close to each
other, in parallel, but the dielectric sits between them to make sure they
don’t touch.

33. Formulae for Capacitor

37.  A capacitor’s capacitance – how many farads
it has – tells you how much charge it can
store. How much charge a capacitor
is currently storing depends on the potential
difference (voltage) between its plates. This
relationship between charge, capacitance,
and voltage can be modelled with this
equation:
Q=CV

38.  Not all capacitors are created equal. Each capacitor is
built to have a specific amount of capacitance. The
capacitance of a capacitor tells you how much charge
it can store, more capacitance means more capacity
to store charge. The standard unit of capacitance is
called the farad, which is abbreviated F.
 It turns out that a farad is a lot of capacitance, even
0.001F (1 milifarad – 1mF) is a big capacitor. Usually
you’ll see capacitors rated in the Pico- (10-12) to
microfarad (10-6) range.

When you get into the farad to kilo farad range of
capacitance, you start talking about special caps
called super or ultra-capacitors.

39.  Capacitors can be categorized on various factors:-
 Size - Size both in terms of physical volume and capacitance.
 Maximum voltage - Each capacitor is rated for a maximum voltage
that can be dropped across it. Some capacitors might be rated for
1.5V, others might be rated for 100V. Exceeding the maximum
voltage will usually result in destroying the capacitor.
 Leakage current - Capacitors aren’t perfect. Every cap is prone to
leaking some tiny amount of current through the dielectric, from one
terminal to the other. This tiny current loss (usually nanoamps or
less) is called leakage.
 Equivalent series resistance (ESR) - The terminals of a capacitor
aren’t 100% conductive, they’ll always have a tiny amount of
resistance (usually less than 0.01Ω) to them.
 Tolerance - Capacitors also can’t be made to have an exact, precise
capacitance.

40.  Ceramic Capacitors:- The most commonly used and
produced capacitor out there is the ceramic capacitor. The
name comes from the material from which their dielectric is
made.
 Aluminium and Tantalum Electrolytic:- Electrolytes are great
because they can pack a lot of capacitance into a relatively
small volume. If you need a capacitor in the range of 1µF-
1mF, you’re most likely to find it in an electrolytic form.
Unfortunately, electrolytic caps are usually polarized. They
have a positive pin – the anode – and a negative pin called
the cathode. When voltage is applied to an electrolytic cap,
the anode must be at a higher voltage than the cathode.
The cathode of an electrolytic capacitor is usually identified
with a ‘-’ marking, and a coloured strip on the case. The leg
of the anode might also be slightly longer as another
indication.
 Super capacitors:-If you’re looking for a capacitor made to
store energy, look no further than super capacitors. These
caps are uniquely designed to have very high capacitances,
in the range of farads.


41. Ceramic Capacitor Aluminium and Tantalum Electrolytic
Super capacitors

42. consider a circuit having only a capacitor and an AC power source. It
turns out that there is a 90 degree phase difference between the current
and voltage, with the current reaching its peak 90 degrees (1/4 cycle)
before the voltage reaches its peak. The AC power supply produces an
oscillating voltage. The larger the capacitance, the more charge has to
flow to build up a particular voltage on the plates, and the higher the
current will be.

43.  An oscillator provides a source of repetitive A.C. signal across
its output terminals without needing any input (except a D.C.
supply). The signal generated by the oscillator is usually of
constant amplitude.
 The wave shape and amplitude are determined by the design
of the oscillator circuit and choice of component values.

44.  SINE WAVE OSCILLATORS produce a sine wave
output.
 RELAXATION OSCILLATORS and ASTABLE
MULTIVIBRATORS produce Square waves and
rectangular pulses.
 SWEEP OSCILLATORS produce sawtooth
waves.

45. RELAXATION OSCILLATORS and ASTABLE
MULTIVIBRATORS

46. An amplifier. This will usually be a voltage amplifier and may be biased in class
A, B or C.
2. A wave shaping network. This consists of passive components such as filter
circuits that are responsible for the shape and frequency of the wave produced.
3. A POSITIVE feedback path. Part of the output signal is fed back to the
amplifier input in such a way that the feed back signal is regenerated, re-
amplified and fed back again to maintain a constant output signal.

47. The feedback in the amplifier section of an oscillator must be POSITIVE
FEEDBACK. This is the condition where a fraction of the amplifier's output
signal is fed back to be in phase with the input, and by adding together the
feedback and input signals, the amplitude of the input signal is increased.
For example, a common emitter amplifier creates a phase change of 180°
between its input and output, the positive feedback loop must therefore also
produce a 180° phase change in the signal fed back from output to input for
positive feedback to occur.

48.  An inductor is a passive electronic component
that stores energy in the form of a magnetic
field. In its simplest form, an inductor consists of
a wire loop or coil. The inductance is directly
proportional to the number of turns in the coil.
Inductance also depends on the radius of the coil
and on the type of material around which the coil
is wound.
 For a given coil radius and number of turns, air
cores result in the least inductance. Materials
such as wood, glass, and plastic - known
as dielectric materials - are essentially the same
as air for the purposes of inductor winding.

49. Working of Inductor

50.  On the basis of power conversion methods.
Power supplies are divided into linear and switching types.
 Linear power converters process the input power directly
with all active power components operating in their linear
operating regions
 Switching power supplies the input power is converted
into AC or to DC pulses before processing.
 Power is lost when components work in their linear
regions and hence switching converters are usually more
efficient than linear converters because their components
spend less time in linear operating ranges.

51. General power supply
Analog IC block diagram of power supply
A high voltage power supply

52. AC TO DC POWER SUPPLY
AC TO DC POWERS SUPPLY CIRCUIT