ATATÜRK
ÜNİVERSİTESİ
MÜHENDİSLİK
FAKÜLTESİ
ELEKTRİK
ELEKTRONİK MÜHENDİSLİĞİ BÖLÜMÜ
ELEKTRONİK
DEVRELER PROJESİ
Project:
WİEN
BRIDGE OSCILLATOR
The
Project Who: BÜLENT
ÇAKMAK
The
Project Prepared By:
AHMET ÖZMEN
SEZER KEMENT
TABLE
OF CONTENTS
Ø
1.
OSCILLATOR?
Ø
2.
WİEN BRIDGE OSCILLATOR INFORMATION ABOUT
·
2.1.
the WORK of the ' 60s OP-AMP CIRCUIT
·
2.2.
TIRANSİSTÖRLÜ OPERATION of the CIRCUIT
Ø
3.
TRY CONSTRUCTION
·
3.1.
TOOLS and EQUIPMENT USED
·
3.2.
OP-AMP ' lı CIRCUIT DIAGRAM
·
3.3
OP-AMP ' L I OPERATION of the CIRCUIT
·
3.4.
the RESULTS of the OP-AMP ' L I
·
3.5.
TRANSISTOR CIRCUIT DIAGRAM
·
">
3.6. TRANSISTOR CIRCUIT OPERATION
·
3.7.
RESULTS of TRANSISTOR CIRCUIT
Ø
4.
EVALUATION of the RESULTS
1.
OSILATÖRLER
Oscillator
What
Is It?
Electronic
messageInc.im
systems and automation systems, square wave, sine wave, triangle wave, or saw
diInc.I
use wave formatsıldpitch
so
sayıread
the applicationır.
..networku
use more than one type of signal and the case these areı
are
it is necessary to synchronize. Dueısıwith
that desired Isa
suitable signal requires the production ofleme.
For example, thenetworkof
a microcontroller
to the
desired programı
can
execute a square wave signal with a trigger is required. This example produces a
square-wave signal, even open the importance of
oscillator
ıcomplex.
The
desired frequency and wave Oscillator
Inc.information
electrical
titreInc.feedback
amplifier that produces marks.
Dinetworkproduces
a signal on its own with a expression of circuits
called "oscillator".
Oscillators
DC
power sourcesıfed
from. As a result of this DC voltage
the
desired
frequency,
and then clickInc.aretlere
returnInc.set
isn't. Oscillators
in control systems and television, radio, radio, AM alıcıs,
AM transmitters, it FM alıcıs
and use systems such as FM transmittersılır.
Electrical titretim
or diðer
nameıwith
oscillation,
wave format
continuous
as
repeated in theðn.Inc.trader.
Cıkbusiness
waveform
sattached
to the sine wave, square wave, triangle wave, saw dis.n.
wave or periodic aralırepeated
any wave klarla scan
be attached. Aslıin
an oscillator,
its inputs 's
signal that assure their own amplifier circuit.
Figure
1.1: the basic oscillator
block diagram
ı
2
An
oscillator
circuit, brought aboutðn.
signals or osilasyonların
(titreInc.Shukriınım)
continue;
ØUpgrade
ØFeed-back
ØAmplitude
limiter and frequency detection and destructive, are needed.
An
oscillator
circuit of the outputıkdo
not expose
then
an amountınınInc.seen
in Figure 1.1
ðü
as inputInc.back
to nutrition is required. Feedback, high level point on a
systemıfrom
a low-level pointına
energy transfer. Diğan expression with cıkofn
inputInc.to
the UTC financial manual againıdır.
feed-back inputsI
artırıcı
is
positive, reduce the directionıcı
direction
is negative feedback. Circuit kayıplarını
and
osilasyonların
due toılpitchnı
sanetworkto
connect the useımadeı
need
feedback positive feedback must beıdır
a frequency to be determined before a oscillator
to detect a frequency oscillation
and destructive, there are neededır.
Oscillator
gto access the feed, frequency detecting circuit, I
felt likeıflamayı
.INC.as
shown in Figure 1.1 in the resonant
circuit, frequency detecting circuit diðEl-aðn.Inc.the
filter circuit passes the desired signals, le is
objectionable bastırıthe
resonance circuit coil and capacitor elements rıfrom
or resistance and capacitor elementsıcreate
from thesur
and these guysın
the names nowılır.
Oscillator
cıkdo
not exposethe
signal amplitude and frequency in theının
fixed to the
oscillator
circuit of the amplifier to the positive feed-back Kirkı
sglı
.
The
most important feature sought frequency Oscillators
struggle. Frequency shift in other words occurring at a frequency of unwanted
changes, it causes very serious errors in control systems. Following are the
main causes of the inclination of the frequency.
Ø
Supply
voltage variations
Ø
Mechanical
tremors
Ø
Heat
exchange
Ø
Freight
Exchange
Necessary
measures against these factors, Oscillator
designs, based on frequency shift to the extent possible, should be
avoided.
2.
WİEN BRIDGE OSCILLATOR INFORMATION ABOUT
2.1.
OP-AMP 'Li
Circuit Study
Wien
bridge oscillator,
both positive and negative feedback uses an RC phase shift osilatörüdür.
Figure 1.5
in the
circuit, as is a high input impedance amplifier OP-AMP used element.
This
oscillator
signal frequencies between 1 MHz with 5 Hz ' batteries, commonly used to produce
stable low-frequency osilatörüdür.
Figure
1.5: Opamplı wien bridge oscillator
As
shown in Figure 1.5
R1-C1 consisting of the serial, R2-C2 consisting of parallel to R-C circuits
Wien bridge. These
elements determines
the frequency. R3 and R4 with yükselteçin
gain is limited. Output signal, a certain amount of the
OP-AMP's
phase inverting (+) input is fed back to the R1-C1 elements. OP-AMP
'in
the
working frequency of the R1-C1, R2-C2 consisting of bridge circuit to a maximum
feedback and this frequency phase angle is zero.
formula
with.
In
addition, the circuit is the desired frequency oscillation
and to provide adequate online earnings (R3/R4) must be > = 2.
During
the total phase shift circuit exactly 0 ° dir.
Extreme low frequencies C1 becomes open circuit and
does not occur in any of the output signal. The extreme high frequencies would
be a short circuit and an output of C2 does not occur.
The
combination of the frequency F, R2-C2 + 45 degree phase advances, while the
combination of R1-C1-45 degree phase delay. This phase advance delay circuit and
R3-R4 ,
omik
voltage divider creates a Wien bridge when the bridge is balanced, the
difference in voltage at a frequency F is equal to zero. Voltage divider
provides the feedback negative or annoying. It also balances the positive
feedback generated advancing delay circuit. From now on, given the frequency of
the desired F Energy commissioned sinusoidal
oscillations in the output is obtained. Figure 1.5 a
adjustable resistor R4 resistor in series by connecting the OP-AMP gain can be
adjusted. In this way, it would be undesirable that may occur as a result of the
extreme upgrade trimmings drops.
2.2.Tıransistörlü
Circuit
Study
In
fact, a two-stage amplifier with a RC Bridge circuit. RC Bridge circuit (Wien
bridge) is a lead-lag
network. Network phase-shift
frequency increases delay and frequency decreases. Wien-Bridge oscillator
the feedback network, adding only a specific frequency, the signal becomes
sensitive. This is balanced and which specific frequency Wien bridge phase shift
0 ° which is. Wien-Bridge if the feedback network employment and transistor
transistor
output 2 Q Q fedback
is 1 necessary to produce oscillations of
regeneration
to ensure the
transistor Q
1 raise a wide frequency range signals, and thus the direct link will cause the
weak frequency stability. Thus the stability of the network by using the
feedback frequency increases, Wien-Bridge.
Bridge
circuit as the series with 1 R 1 C, R -3,
R-
4 and R 2 C 2 form in parallel with the four arms.
This
bridge circuit through the amplifier's phase difference must be zero, provided
that an oscillator
can be used as feedback for the network. As shown in the figure, this is
achieved using a two-stage amplifier, the condition of the situation
.In
this arrangement,
the second stage is fed back to the network output feedback and voltage across a
parallel combination of C 2 R 2, the first is the stage entrance. Transistor
Q 1 transistor
Q is an oscillator
and amplifier serves as the 2 inverter
180 ° phase shift. The
circuit uses positive and negative feedback .Positive
feedback
R through 1 C 1 R 2 C 2 transistor
for Q 1 and negative feed back of
the transistor
voltage divider input switches to Q 1. Resistors R 3 and R 4 the output amplitude
is used to stabilize
.
Two
transistor
Q 1 Q 2 reason why total 360 ° phase shift and positive feedback .Over
a frequency range of hard back to the negative output
to ensure the circuit is available. This resistance is the resistance of the
flow increased in 4 of R ,
with
a heat-sensitive lamp, form. In case the output amplitude, will provide more up
to date than to increase the negative feedback. Thus, the output of the original
value of the won again. The
output will be a falling trend in reverse action.
3.
TRY CONSTRUCTION
3.1.
theUsed
Vehicle
and Equipment
·
RESISTANCE
(1 k, 2 K, 3 K, 10 k, 12 k, 15 k, 7 K, 22 k, 24 k, 27, 39 k)
·
POT-HG
(1 k, 5 k, 10 k)
·
Transistor
(BC546)
·
OP-AMP
(UA741)
·
CAPACITOR
(10nF, 033 uF, 10uF, 1uF)
·
Diode
(1N914)
Our
circuit C1, R4 series RC circuit and C2, R5 parallel RC circuit WİEN
BRIDGE .
This part is also the oscillator
RESONANT
part.
Part of the output that we didn't have the resonance
frequency. From here, the Op-Amp's
inverting (+) input phase POSITIVE
FEEDBACK
was
provided. Phase shift for the (+) end is connected.
During
the total phase shift circuit exactly 0 ° dir.
Extreme low frequencies C1 becomes open circuit and
does not occur in any of the output signal. The extreme high frequencies would
be a short circuit and an output of C2 does not occur.
Circuit,
R1, R2, R3, RV1 resistances of the OP-AMP's
components that determine the coefficient for the upgrade.
OP-AMPS and resistors AMPLIFIER
part. To make a good upgrade to 2 times the RV1 resistance R1, R2 and
R3 must be selected. Diodes D1 and D2, while tıkamada (the amplitude of the signal from the very young)
R3 and R1 serial equivalent. Transmission (amplitudes is higher) when the
R2 and R3 are resistor parallel equivalent. In this way, we have provided the
highest earnings. RV1 adjustable resistor sets the gain of the OP-AMP 'in . In this
way, the signal kırpılmaların are prevented.
Located
at the exit of the circuit voltage divider resistors R6, R7 and the desired
output amplitude signal through us RV2.
Wien
bridge consisting of frequency small signal,
positive
feedback is provided by continuum. OP-AMP and we build this small signal. Thanks
to the desired amplitude adjustable resistors and properly obtained a sine or
square wave.
3.4.
the results of the OP-AMP ' l ı
C=C1=C2=10nF
The
resistance of the circuit to obtain a smooth sinus has been set using frequency
changes. F
= 1 kHz sine wave consisted of up to 1.3 kHz from the verimlisi F = 1,063 kHz.
F
= 1.3 kHz kHz square wave produced from 1.6.
The
verimlisi is F = 1.515 kHz also
occurred.
3.5.Transistor
Circuit Diagram
Our
circuit C3, R4 series RC circuit and C4, R8 parallel RC circuit WİEN
BRIDGE .
This part is also the oscillator
RESONANT
part.
Part of the output that we didn't have the resonance
frequency.
R4,
C3 and Q2 's collector
of POSITIVE
FEEDBACK
.
Positive
back to
the feed because the Q1 transistor
180 degree phase shift and on the second floor, Q2 transistörününde
180 degrees phase kaydırmasıdır. This reason,
Q2
,
introducing an output from a total of 360-degree phase shift because "0"
lanmıştır.
Transistors
Q1 and Q2 oscillator
circuit of the YÜKLELTEÇ
part
of the. With the most efficient upgrade rate captured RV1 Other resistors in the circuit to the most efficient
transistors
Q1 and Q2 provides a workspace.
Wien
bridge consisting of frequency small signal,
positive
feedback continuum . Transistors
with this signal.
Adjustable resistance to correct the
output.
2.3.Transistor
Circuit
Results
Oscillator
circuits, RESONANCE,
the AMPLIFIER
and
the FEEDBACK
portion.
Resonant circuit as the WİEN
BRIDGE, nude. Wien bridge, the R and
C values of the phase difference according to the frequency selected and not
determined. Phase difference to avoid POSITIVE
feedback.
Amplifier as part of OP-AMP
and
the
TRANSISTOR
is
used. Double-storey common emitter
transistors with
phase difference "0" completed, the OP-AMP ' in
feedback based on phase difference was prevented from inverting. Amplifiers
kutuplayan
provided a good selection of good signal resistors
.
FATİH
YAVİLİOĞLU AND
SEZER KEMENT’ E THANK YOU