basic-analog-electronics

1. 1
Basic Practical ElectronicsBasic Practical Electronics
Passive components
Resistors, Capacitors, Inductors, Transformers, Diodes etc.
Circuits
Circuit analysis, voltage sources, current sources
Analog Electronics
Transistors, Opamps, Simple analog Electronics circuits
Digital Electronics
Basic Logic Gates and basic ICs, uPs, RAMs,
ROMs, ADCs, DACs, PALs etc.

2. 2

3. 3
When selecting a
resistor for a circuit,
there are three
parameters to
consider
1. Resistance (Ω)
2. Power rating (W)
3. Tolerance (%)
4. Type???

4. 4
TYPES OF RESISTORS
Carbon
Composition
Carbon mixed with a
binder. Molded and
baked. Ratio of
carbon to binder
determines
resistance. Most
common. Tolerances
10%.
CIRCUIT SYMBOLS
Carbon Film Better temp stability
Metal Film Better Tolerance 1%
Metal Oxide Better Temperature
stability and
Tolerance (used
in Most Logging
Equipment)
Wire wound

5. 5
WIRE WOUND: A conducting wire is wound on
a ceramic form. Tend to be physically large.
Low resistances. High power capability.
Tolerances around 1%. Figure 1-8 shows some
wire wound resistors.
XAMPLE OF WIRE WOUND
RESISTOR Three terminal variable resistors

6. 6
COLOUR CODING OF RESISTORS
B
B
R
O
Y
G
B
V
G
W

7. 7
CAPACITORS
A capacitor is a device that stores energy as electrical
charge on it's plates.
The stored energy has to be a DC Voltage. This leads to capacitors acting
like OPEN for DC while SHORT for AC
These plates are placed very close together with an Dielectric (insulator)
in between.
Capacitance of a capacitor depends on the Area of two plates, how close
they are and the dielectric type.
Capacitor parameters are
1. Capacitance value (uF –MicroFarads)
2. Voltage Rating (V)
3. Type

8. 8
Most commonly used capacitors
Made of electrolyte, Aluminum electrodes. Most
common polarized capacitor (They have a +ve and –ve
terminal)
•Applications: Ripple filters, timing circuits.
•Not very accurate, high values of capacitance, have
leakage, drifting, not suitable for use in hf circuits.
•They WILL explode if the rated working voltage is
exceeded or polarity is reversed, so be careful.
Electrolytic Capacitors

9. 9
Made of Tantalum Pentoxide. They are electrolytic
capacitors but used with a material called
tantalum for the electrodes. Superior to aluminum
electrolytic capacitors, excellent temperature and
better frequency characteristics.
Used in Logging Tools
More expensive than Aluminum but smaller size
Tantalums are also polarized so watch the '+' and
'-' indicators.
Tantalum Capacitor

10. 10
Super Capacitors have very large capacitance
value.
These are popular in DeskTop PCs and SMPS
Not used in Logging Tools
Super Capacitors

11. 11
Other types
Polyester Film
Tuning or 'air-core' capacitors.
Multilayer Ceramic
Metalized Polyester Film
Adjustable
Capacitors

12. 12
If a capacitor is marked like this 105, it
just means 10+5zeros = 10 + 00000 =
1.000.000pF = 1000 nF = 1 µF
CAPACITOR CODING

13. 13
Capacitors in Parallel
C total = C1 + C2 + C3
Keep in mind that only the total capacitance
changes, not the supplied voltage.
Capacitors in Series

14. 14
INDUCTORS
Inductor is essentially a device which stores
energy in the form of magnetic field.
Common uses of Inductors are as Filter coils.
Most Important use is in Transformers, Relays

15. 15
TYPES OF INDUCTORS
BAR-COIL
SURFACE MOUNT
THIN FILM
The surface mount type
inductors are very small in
size and therefore deserve
to be considered when
space
becomes and issue.
TOROIDAL
The surface mount type inductors are
very small in size and therefore
deserve to be considered when space
becomes and issue.

16. 16
TransformerTransformer
Step down Step Up
Transformers
work for AC
Only
Vp = Np = Is
Vs Ns Ip
The core is usually
made of Iron and is
laminated

17. 17
RELAYsRELAYs
Relays are
electromagnetic
switches which can
be made to either
SWITCH ON or OFF
depending on the
current in their coil
A Relay has the following
Pin connections below
NC – Normally Closed
NO – Normally Open
COM – Common
Coil -

18. 18
Some Typical Circuits - Voltage Divider
1) With two resistors in series, the
sum of the voltage drop across
each equals the total voltage
drop across both.
2) To determine the voltage
between the two resistors, we
use the voltage divider formula
3) The voltage divider formula
says Vout = Vin* (R2/R1+R2)
4) This turns out to be very useful

19. 19
Passive Components - Diodes
Schematic Symbols for
DIODES
Diode is a electronic device that allows
current to flow in one direction ONLY
There are many type of Diodes. Some basic types are
1. Rectifier Diode
2. Zener Diode
3. Light emitting Diode

20. 20
DIODE, Transformer, Capacitor APPLICATIONS
Rectifiers
During the negative part of the cycle D1 does not
conduct and no current flows to the load. In the full
wave application it essentially is two half wave rectifiers
combined and because the transformer secondary is
centre tapped, D1 conducts on the positive half of the
cycle while D2 conducts on the negative part of the
cycle. Both add together.

21. 21
DIODE APPLICATIONS
Zener diodes work on the principle of
essentially a constant voltage drop at a
predetermined voltage
Voltage regulators

22. 22
OTHER DIODE APPLICATIONS
LEDs
LEDs usually have Gallium Arsenide Phosphide
Photodiodes
Opto-Coupler
Opto-Isolator

23. 23
1N34A Germanium Diodes
Germanium diodes have the advantage of an
intrinsically low forward voltage drop, typically
0.3 volts; this low forward voltage drop results in
a low power loss and more efficient diode, making
it superior in many ways to the silicon diode. A
silicon diode forward voltage drop, by
comparison, is typically 0.7 volts. This lower
voltage drop with germanium becomes important
in very low signal environments (signal detection
from audio to FM frequencies) and in low level
logic circuits. As a result germanium diodes are

24. 24
Voltage and Current SourcesVoltage and Current Sources
An ideal voltage source is a voltage source
that maintains the same voltage across
the source's terminals no matter what
current is drawn from the terminals of the
source or what current flows into the
terminals
Similarly an Ideal
current source would
source the same
amount of current no
matter what voltage
develops

25. 25
Circuit Analysis 1Circuit Analysis 1
L R1 R2
R5
R3
R4
V
In the Electrical circuit below what is the voltage across R3 and current in R4
C
12V
L= 2H, C= 1uF, R4=6 ohms, R2=4
ohms, R3=2 ohms, R1=3 ohms

26. 26
Circuit Analysis 2Circuit Analysis 2
Input is Sinewave Plot output
2.5V.
All three diodes are general purpose Silicon Diodes

27. 27
Circuit Analysis 3Circuit Analysis 3
Two Electrical Bulbs each of 220V, 40W rating are connected in the manner shown
A. B.
220V Bulb1 Bulb2
220V Bulb1 Bulb2
Total light in Case A ________________ Total light in Case B (choices GT, EQ, LT)
Voltage Across Bulb1 Case A = _______ Volts, Current in Bulb2 Case B = _______

28. 28
TRANSISTORS
Transistors are semiconductor
electronic devices that can amplify
currents or voltages when configured
properly
There are many types of Transistors. For selecting a Transistor we
need to know the application desired (type of Transistor, Voltage
(power rating) and max frequency of operation

29. 29
Most Transistors have three leads which must
be connected the correct way round.
These days Transistors come in a variety of
packages and sometimes can be difficult to
recognize

30. 30
Besides Amplifying Transistors can
also be connected as a Switch
TEST CIRCUIT for
Transistor as a Switch
We use this type of
configuration typically
inside our Logging
Equipment to activate
RELAYs by sending a
remote control signal
to the base of the
Transistor

31. 31
DARLINGTON PAIR:
Sometimes we need to amplify and
handle large currents
1. Controlling Relays
2. Driving Loudspeakers
In such cases we put a Small Signal
Transistor TR1 (high gain but low
current) in series with a Power Transistor
TR2 (low gain but high current) as
shown
The resulting composite Transistor is
called a Darlington Pair. A Darlington
Pair has High Gain as well as High Power
One can make the Darlington Pair by
using two separate Transistors or buy
TRANSISTOR APPLICATIONS

32. 32
Simple Transistor Amplifier
Given below is a standard Common Emitter AC Amplifier. Transistor is Silicon NPN
Assume hfe (β) >> 100, Vbe = 0.7V
In
Out19.2 K 9.4K
10.8 K
4.7 K
+15V
AC Gain of the circuit = ________
DC Voltage at base of Transistor is _____
DC Voltage at Collector of Transistor is ______
DC Voltage at Emitter of Transistor is _______
DC Current from Collector to Emitter is ________

33. 33
One use of phase splitters is to provide input signals
to a single-stage amplifier that uses two
transistors. These transistors are configured in such
a way that the two outputs, 180º out of phase with
each other, combine. This allows more gain than
one transistor could supply by itself. This "push-pull"
amplifier is used where high power output and good
fidelity are needed:
PUSH-PULL AMPLIFIERS

34. 34
AMPLIFIER FREQUENCY RESPONSE
BANDWIDTH OF AN AMPLIFIER
The bandwidth represents the amount or
"width" of frequencies, or the "band of
frequencies," that
the amplifier is MOST effective in
amplifying.
B.W = f2-f1

35. 35
Analog Electronics –
Operational Amplifiers
The input stage is a differential amplifier that works for AC also
High Input impedance
High Gain Voltage Amplifier. Typical > 100,000
Low Output Impedance to deliver several mA of current into load connected to the Output.

36. 36
Op Amps ApplicationsOp Amps Applications
Common applications:
• Inverting amplifier
• Non inverting amplifier
• Summing amplifier
• Voltage follower
• Instrumentation amplifiers
• Filters

37. 37
Non-inverting AmplifierNon-inverting Amplifier
IN
1
2
o V
R
R
1V 





+=
R1
R2
VIN
Vo
I=0

38. 38
Inverting AmplifierInverting Amplifier
V0
+
−
R1 R2
VIN
Input Loop
Feedback Path
Output Loop
IN
1
2
o V
R
R
V −=
I=0

39. 39
V1
V0
+
−V3
V2
RF
R1
R2
R3
3
3
F
2
2
F
1
1
F
0 V
R
R
V
R
R
V
R
R
V −−−=
Summing Amplifier-MixerSumming Amplifier-Mixer
Also used in DACs – will see later

40. 40
Voltage followerVoltage follower
• Vout(ideal) = Vin
• High input resistance Rin
• Low output resistance
Used as a buffer
stage between any
two electronic
devices. Why?

41. 41
IInstrumentationnstrumentation AAmplifiermplifier

42. 42
Op Amp ChallengeOp Amp Challenge

43. 43
Filter TerminologyFilter Terminology
• Pass band is the range of frequencies over
which it will pass an incoming signal
• Low pass filter pass low-frequency signal
• High pass filter pass high frequency signals
• Band pass filter passes a limited range of
frequencies
• Band stop filters block signals occurring
between two given frequencies

44. 44
Filters
Background:
. An activeactive filterfilter is one that, along with R, L, and C
components, also contains an energy source, such
as that derived from an operational amplifier.
. A passive filterpassive filter is one that contains only R, L, and
C components. It is not necessary that all three be
present. L is often omitted (on purpose) from
passive filter design because of the size and cost
of inductors – and they also carry along an resistance(r) that
must be included in the design.

45. 45
Passive FiltersPassive Filters
• Passive Components
– Resistors
– Capacitors
– Inductors
• Use No Amplifying Elements
– Transistors
– Operational Amplifiers

46. 46
Passive FilterPassive Filter
• No transistor, diodes, etc
• Gain is always <= 1
• Output load become part of circuit
• Simplest electronic filters (consist of
resistors,inductors and capacitors)
• Since resistance has the symbol R, inductance
the symbol L and capacitance symbol C, so filters
exist in so-called RC, RL, LC and LCR varieties

47. 47
How Passive Filters WorkHow Passive Filters Work
• Capacitors
– Block low frequency signals
– Conduct high frequency signals
• Inductors
– Block high frequency signals
– Conduct low frequency signals
• Resistors
– Have no frequency-selective properties

48. 48
Passive Analog Filters
Background: Four types of filtersFour types of filters - “Ideal”- “Ideal”
lowpasslowpass highpasshighpass
bandpassbandpass bandstopbandstop

49. 49
Background: RealisticRealistic FiltersFilters::
lowpass highpasshighpass
bandpassbandpass bandstopbandstop
Passive Analog Filters

50. 50
Passive Analog Filters
Low Pass Filter Consider the circuit below.
R
C
VI
VO
+
_
+
_
1
( ) 1
1( ) 1
OV jw jwC
V jw jwRCRi
jwC
= =
++
Low pass filter circuit

51. 51
Passive Analog Filters
High Pass Filter Consider the circuit below.
C
RVi VO
+
_
+
_
( )
1( ) 1
OV jw jwRCR
V jw jwRCRi
jwC
= =
++
High Pass Filter

52. 52
Active FilterActive Filter
• Combination of passive components and
amplifiers
• High Q value
• Able to achieve resonance frequency without
the use of inductors

53. 53
Low Pass Active Filter
R
C
-
+
Ra
Rf
X(s)
Y(s)
RC
s
RC
R
R
sH
a
f
1
1
1)(
+












+=

54. 54
High Pass Active FilterHigh Pass Active Filter
• Simplified Circuit
– Differentiator
• Response
– At high frequencies
the capacitor acts
as a short. The
gain becomes
-R1/R2
– At low frequencies
the capacitor is
open and the signal
is lost

55. 55
High Pass Active Filter
These are similar to active low pass filters, and may be
constructed by cascading first- and second-order sections.
Here’s a first-order section:
R
C
-
+
Ra
Rf
X(s)
Y(s)
RC
s
s
R
R
sH
a
f
1
1)(
+






+=

56. 56
Required Filter OrderRequired Filter Order
Typically, we will have a requirement for a filter with a
particular pass band, stop band, minimum/maximum pass
band gain, and minimum stop band attenuation. The first
thing we need to do is choose the filter type and order.
We’ll assume the type has already been chosen, so we
need to determine the order.

57. 57
V i n
R 1
R 1
C 1
C 2
R 2
R 2
R f b
R i
V O
+
+
_
_
Band pass(100-200Hz) filter
fr2=200Hz fr1=100Hz

58. 58
V i n
R 1
R 1
C 1
C 2
R 2
R i
R f b
V O
+
_
+
_
Band stop(100-200Hz) filter
fr2=100Hz
fr2=200Hz

59. 59
ReviewReview
In Logging we have to deal with Basic Electronics
Passive Electrical circuits consist of Resistors,
Capacitors, Inductors, Transformers, Diodes
Active Electronics circuits consist of active devices like
Transistors, Op-Amps plus passive components
Understanding of Basic Circuits like Amplifiers, Filters,
Buffers, Mixers, Power supplies is important