19 Ekim 2013 Cumartesi



The Project Who:           BÜLENT ÇAKMAK
The Project Prepared By:   AHMET ÖZMEN
                                         SEZER KEMENT
                                         FATİH YAVİLİOĞLU

                                         TABLE OF CONTENTS
·       2.1. the WORK of the ' 60s OP-AMP CIRCUIT
·       3.1. TOOLS and EQUIPMENT USED
·       3.3 OP-AMP ' L I OPERATION of the CIRCUIT
·       3.4. the RESULTS of the OP-AMP ' L I

                          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
An oscillator circuit, brought aboutðn. signals or osilasyonların (titreInc.Shukriınım) continue;
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 toılpitch 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.

2.1. 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.
      Circuit R3-R4 and OP-AMP ' part of the riser. The output signal frequency and the frequency of the circuit is sinusoidal ;

formula with.

If you enabled R1 = R2 = R and C1 = C2 = C as is selected in the formula;

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)

3.2. OP-AMP ' circuit diagram

                  3.3 OP-AMP ' l ı operation of the circuit
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

 R=R4=R5=15k Ω          

   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

                      3.6.Transistor Circuit Operation
    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 .