PROJECT REPORT SHEET

parkagendaΗλεκτρονική - Συσκευές

2 Νοε 2013 (πριν από 3 χρόνια και 11 μήνες)

93 εμφανίσεις

PROJECT REPORT SHEET


PROJECT DESCRIPTION:



NAME:


HYEONGRAE KIM

STUDENT ID:


C
05723


1.)

Identify and list all material and components required for this project:


-

Resistors, Wires, Capacitors, PNP transistor, NPN transistor, Diodes


2.)

Identify and list the too
ls required to complete this project:


-

Breadboard, alligator clips, Power supply, power lead, Oscilloscope,

Transformer, Multi
-
meter


3.)

Describe steps required to complete this project:


S
tep.1
To build following these schematic diagram
.

S
tep.2 To check Vou
t and Vin to use multi
-
meter.

S
tep.3 To check Vout and Vin to use oscilloscope.

S
tep.4 To note measuring voltage and graph.


Complimentary
-
Symmetry class B


1.

Standard Push
-
Pull Amplifier


2.

Class AB Amplifier


3.

Dual Polarity Class AB Amplifier


4.

Transistor
Biased Amplifier


5.

Single Capacitor input

6.

Transistor Diven input


7.

Darlington Class AB Amplifier




4.)

Briefly describe circuit operation:



-

C
lass A amplifier

Common emitter voltage amplifiers are the most commonly used type of
amplifier as they have a large

voltage gain. They are designed to produce a
large output voltage swing from a relatively small input signal voltage of only
a few millivolt's and are used mainly as "Small Signal Amplifiers" as we saw
in the previous tutorials. However, sometimes an ampl
ifier is required to drive
large resistive loads such as a loudspeaker and for these types of applications
where high switching currents are needed
Power Amplifiers

are required.

The
main function of the Power amplifier, which are also known as a "Large
Si
gnal Amplifier" is to deliver power, which is the product of voltage and
current to the load. Basically a power amplifier is also a voltage amplifier the
difference being that the load resistance connected to the output is relatively
low, for example a lou
dspeaker of 4 or 8Ωs resulting in high currents flowing
through the Collector of the transistor. Because of these high load currents the
output transistor(s) used for power amplifier output stages need to have higher
voltage and power ratings than the gene
ral ones used for small signal stages.

Since we are interested in delivering maximum AC power to the load, while
consuming the minimum DC power possible from the supply we are mostly
concerned with the "Conversion Efficiency" of the amplifier. However, one

of
the main disadvantage of power amplifiers and especially Class A type
amplifiers is that their overall conversion efficiency is very low. Percentage
efficiency in amplifiers is defined as the r.m.s. output power dissipated in the
load divided by the to
tal DC power taken from the supply source as shown
below.

-

C
lass B amplifier


To improve the full power efficiency of the previous Class A type amplifier it
is possible to design the amplifier circuit with two transistors in its output
stage producing a "
pu
sh
-
pull
" type amplifier configuration. Push
-
pull
operation uses two "complementary" transistors, one an NPN
-
type and the
other a PNP
-
type with both power transistors receiving the same input signal
together that is equal in magnitude, but in opposite phase

to each other. This
results in one transistor only amplifying one half or 180
0

of the input
waveform while the other transistor amplifies the other half or remaining 180
0

of the waveform with the resulting "two
-
halves" being put back together at the
outpu
t terminal. This pushing and pulling of the alternating half cycles by the
transistors gives this type of circuit its name but they are more commonly
known as
Class B Amplifiers

as shown below


-

C
lass AB amplifier


Class 'AB' amplifiers use two groups of tr
ansistors like class 'B' amplifiers. In
most respects, class 'AB' and class 'B' amplifiers are very similar. As we said
earlier, a class 'A' amplifier is very inefficient. This is not good for a car audio
amplifier. Some people believe that class 'B' ampli
fier can never produce
clean audio because their output transistors aren't biased 'on'. A class 'AB'
amplifier is generally considered to be the best compromise. A class 'AB'
amplifier is a class 'B' amplifier which has a small

amount of bias

current
flowi
ng through the output transistors at all times. This eliminates virtually all
of the crossover distortion that's possible with class 'B' amplifiers. The bias
current is flowing because the output transistors are always conducting current.
This differs from

a pure class 'A' amplifier in the amount of current flow. A
pure class 'A' amplifier typically has an enormous amount of current flowing
throug
h its output transistors with
no

audio signal. A

pure class 'B' amplifier
has
no

current flowing through its out
puts with no audio signal. A class 'AB'
amplifier is much more efficient than the class 'A' but without the possible
distortion of the class 'B'.
Many

of the car audio amplifiers which claim to be
a class 'A' amplifier are just a high bias class 'AB' desig
n. These amplifiers are
only class 'A' at very low power output levels. At higher power levels, one of
the output transistors will switch off while the other output transistor is
conducting. I don't want you to think that I am telling you that there are no

class 'A' amplifiers. There are a few high quality mobile amplifiers which are
a true class 'A' design.



5.)

Suggested application(s):

-

V
accum tube amplifier, negative amplifier, radio, speaker, audio


6.)

Your observations and comments (if any):




7.)

After complet
ion, test the functionality of the device against requirements.



T
o check Vin and Vout voltage and graph to use multi
-
meter and
oscilloscope.

A
nd to compare Vin and Vout graph.


-

Complimentary symmetry Class B


-

S
tandard push pull Amplifier


-

Class AB Ampli
fier




















-

Dual Polarity Class AB Amplifier


-

Transistor biased Amplifier


-

Transistor driven input


-

Darlington Class AB Amplifier


Diagnose and rectify faults


Does the device operate correctly after completion?
yes

If no, complete section
s below.



1.)

Describe in detail the action(s) taken to diagnose the fault:

na



2.)

Describe in details the action(s) taken to rectify the fault:

na


3.)

List the faulty component(s) and/or adjustments required to rectify the fault:



na



4.)

Identify the tools required to diagnose the fault:


na



5.)

Identify all material and components required to rectify the fault:


na




6.)

Identify the tools required to rectify the fault:

na