Triangular Wave Oscillator Circuit Diagram

Triangular Wave Oscillator Circuit Diagram. This design resulted from the need for a partial replacement of the well-known 8038 chip,  which is no longer in production and there fore hardly obtainable. 

An existing design for driving an LVDT sensor (Linear Variable Differential Transformer),  where the 8038 was used as a variable sine  wave oscillator, had to be modernised. It may  have been possible to replace the 8038 with an  Exar 2206, except that this chip couldn’t be used  with the supply voltage used. For this reason we  looked for a replacement using standard components, which should always be available.

In this circuit two opamps from a TL074 (IC1.A  and B) are used to generate a triangular wave,  which can be set to a wide range of frequencies using P1. The following differential amplifier using T1 and T2 is configured in such a way  that the triangular waveform is converted into  a reasonably looking sinusoidal waveform. P2  is used to adjust the distortion to a minimum. 

Triangular Wave Oscillator Circuit Diagram

Triangular Wave Oscillator Circuit Diagram

The third opamp (IC1.C) is configured as a  difference amplifier, which presents the sine  wave at its output. This signal is then buffered by the last opamp (IC1.D). Any offset at the  output can be nulled using P3.

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Low Power 32kHz Oscillator Circuit Diagram

The 32-kHz low-power clock oscillator offers numerous advantages over conventional oscillator circuits based on a CMOS inverter. Such inverter circuits present problems, for example, supply currents fluctuate widely over a 3V to 6V supply range, while current consumption below 250 µA is difficult to attain. Also, operation can be unreliable with wide variations in the supply voltage and the inverter’s input characteristics are subject to wide tolerances and differences among manufacturers. The circuit shown here solves the above problems. Drawing just 13 µA from a 3V supply, it consists of a one-transistor amplifier/oscillator (T1) and a low-power comparator/reference device (IC1).

The base of T1 is biased at 1.25 V using R5/R4 and the reference in IC1. T1 may be any small-signal transistor with a decent beta of 100 or so at 5 µA (defined here by R3, fixing the collector voltage at about 1 V below Vcc). The amplifier’s nominal gain is approximately 2 V/V. The quartz crystal combined with load capacitors C1 and C3 forms a feedback path around T1, whose 180 degrees of phase shift causes the oscillation. The bias voltage of 1.25 V for the comparator inside the MAX931 is defined by the reference via R2. The comparator’s input swing is thus accurately centred around the reference voltage.

Very Low Power 32kHz Oscillator Circuit Diagram

Operating at 3 V and 32 kHz, IC1 draws just 7 µA. The comparator output can source and sink 40 mA and 5 mA respectively, which is ample for most low-power loads. However, the moderate rise/fall times of 500 ns and 100 ns respectively can cause standard, high-speed CMOS logic to draw higher than usual switching currents. The optional 74HC14 Schmitt trigger shown at the circuit output can handle the comparator’s rise/fall times with only a small penalty in supply current.

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1:800 Oscillator

Oscillators are ten a penny, but this one has something special. Its frequency can be adjusted over a range of 800:1, it is voltage controlled, and it switches off automatically if the control voltage is less than approximately 0.6 V. As can be seen from the chart, the characteristic curve f = f(Ue) is approximately logarithmic. If the input voltage is less than 0.7 V, T1 and T3 are cut off. The capacitor then charges via the 10-kW resistor. The combination of the capacitor, the two Schmitt triggers and T2 form the actual oscillator circuit. However, T2 cannot discharge the capacitor, because T3 is cut off.

In this state, a low level is present at A1 and a high level is present at A2. If the input voltage is increased, T3 starts conducting. This allows the capacitor to be discharged via T2, and the circuit starts to oscillate. If Ue is further increased, the capacitor receives an additional charging current via T1 and the l00-Ω resistor. That causes the oscillator frequency to increase. In situations where the duty cycle of the output signal is not important (such as when the circuit is used as a clock generator), this circuit can be used as a voltage-controlled oscillator (VCO) with a large frequency range and shutdown capability. 

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50 to 300 MHz Colpitts Oscillator Circuit Diagram

Simple high efficiency Colpitts oscillator .In the higher frequency ranges, above 50 MHz, Colpitts oscillators are used because stray circuit capacitance will be in parallel with desired feedback capacitance and not cause undesirable spurious resonances that might occur with the tapped coil Hartley design.

The FM VCO shown is a grounded base design with feedback from collector to emitter. A Colpitts oscillator is one of a number of designs for electronic oscillator circuits using the combination of an inductance with a capacitor for frequency determination.As you can see in the circuit diagram , this electronic project require few electronic parts an provide a 50 MHz-300MHz VCO with a tuning range of 2:1 .

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Oscillator 50-300 MHz Colpitts Type Circuits Diagram

This is the simple project of Oscillator 50-300 MHz Colpitts Type Circuits Diagram. Simple but high efficiency of this circuit is a Colpitts oscillator for VHF. Ideal for higher frequencies above 50 MHz, Colpitts oscillators are used for VHF parasitic capacitance of the circuit is in parallel with the feedback capacitance desired and causes no undesired spurious resonances which may occur with the Hartley oscillator.

The circuit above is a VCO FM, it is a grassroots project with grounded feedback from collector to emitter. A Colpitts oscillator is a series of designs for electronic oscillator circuits using a combination of an inductance with a capacitor to determine the frequency.

Make an Oscillator 50-300 MHz Colpitts Type Circuits Diagram

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Oscillator Sine wave Circuit Diagram

This circuit is a sine wave oscillator which uses operational amplifiers working in oscillation back (positive feedback), or the oscillation output to the input. This oscillator is called Wien bridge circuit is often used. The oscillator Sine wave oscillator is difficult to be done due to the distortion of the oscillation signal, different oscillator square wave, triangle wave oscillator (sawtooth).

Oscillator Sine wave Circuit Diagram

In the case of C1 = C2 = C, R = R1 = R2, giving the frequency of oscillation and can be calculated using the following formula.

Formula Sine Wave Oscillator

The example of the circuit was made this time is shown below.
f = 1 / (2 x 3.14 x 10 -6 0.01 x 10 x 15 x 3)

f = 1 / (0.942 x 10 -3)

f = 1.062 x 10 3

f = 1062 Hz

The actual frequency of the circuit was 900 Hz.

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Comparator Based Crystal Oscillator Circuit Project

This is simple Comparator Based Crystal Oscillator Circuit Project. Although a simple crystal oscillator may be built from one comparator of an LT1720/LT1721, this will suffer from a number of inherent shortcomings and design problems. Although the LT1720/LT1721 will give the correct logic output when one input is outside the common mode range, additional delays may occur when it is so operated, opening the possibility of spurious operating modes. Therefore, the DC bias voltages at the inputs have to be set near the center of the LT1720/LT1721’s common mode range and a resistor is required to attenuate the feedback to the non-inverting input. Unfortunately, although the output duty cycle for this circuit is roughly 50%, it is affected by resistor tolerances and, to a lesser extent, by comparator offsets and timings.

Comparator Based Crystal Oscillator Circuit Diagram

If a 50% duty cycle is required, the circuit shown here creates a pair of complementary outputs with a forced 50% duty cycle. Crystals are narrow-band elements, so the feedback to the non-inverting input is a filtered analogue version of the square-wave output. The crystal’s path provides resonant positive feedback and stable oscillation occurs. Changing the non-inverting reference level can vary the duty cycle. The 2k-680Ω resistor pair sets a bias point at the comparator + (Comparator IC1a) and – (Comparator IC1b) input. At the complementary input of each comparator, the 2k-1.8k-0.1µF path sets up an appropriate DC average level based on the output.
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IC1b creates a complementary output to IC1a by comparing the same two nodes with the opposite input. IC2 compares band-limited versions of the outputs and biases IC1a’s negative input. IC1a’s only degree of freedom to respond is variation of pulse width; hence the outputs are forced to 50% duty cycle. The circuit operates from 2.7V to 6V. When ‘scoping the oscillator output signal, a slight dependence on comparator loading, will be noted, so equal and resistive loading should be used in critical applications. The circuit works well because of the two matched delays and rail-to-rail outputs of the LT1720.

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Low Distortion Wien Bridge Based Oscillator Circuit Project

This is a very Low Distortion Wien Bridge Based Oscillator Circuit Diagram Project.This complex oscillator circuit uses a photocell and common-mode-suppression circuitry to achieve distortion of 0.0003%. This oscillator circuit replaces the lamp in the traditional Wien bridge with an electronic equivalent. 

Very Low Distortion Wien Bridge Based Oscillator Circuit Diagram 

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Function Generator Circuit Project

This is a simple Function Generator Circuit Project. Simple triangle-wave generators have a weakness in that the waveform of their output signal normally cannot be modified. The circuit presented here makes it possible to smoothly alter the waveform of a linearly rising and steeply trailing saw-tooth signal through a symmetrical triangle-wave to a slowly trailing, steeply rising linear sawtooth. The wanted waveform may be selected independently of the frequency, which can also be varied uniformly from 0.2 Hz to 8 kHz. At the same time, a rectangular signal with variable duty cycle (also independent of frequency) is available at the rectangular-signal output of the circuit.

Function Generator Circuit Project

 
The circuit consists of integrator IC1b, whose output is applied to comparator IC1c. The output of the comparator is a rectangular signal The output of IC1b is raised by amplifier IC1d to a level that allows the full output voltage range of the operational amplifier to be used. Op amp IC1a provides a stable virtual earth, whose level is set to half the supply voltage with P1. The smooth setting of the frequency is made possible by feedback of part of the output of the comparator to the input of the integrator via P2. This preset is usually not provided in standard triangle-wave generators. Network D1-R1-D2-R2-P3 makes it possible to give integrator capacitor C3 different charging and discharge times.

This arrangement enables the output signal at A1 and the duty cycle of the rectangular wave signal at A2 to be varied. Varying the amplification factor with P5 has no effect on the frequency set with P2. The slope of the signal edges, the transient responses, and the output voltage range (rail-to-rail or with some voltage drop) depend on the type of op amp used. The TL084 used in the prototype offers a good compromise between price and meeting the wanted parameters. The circuit is best built on a small piece of prototyping board. The circuit draws a current of not more than 12 mA.

Brief parameters:

Provides triangle-wave, sawtooth or rectangular signal
Waveform variable independently of frequency (triangle wave and sawtooth)
Duty cycle of rectangular signal can be set independently of frequency

Applications:

Test and measurement
Pulse-width control
Summary of preset action:
P1 – sets virtual earth to a level equal to Ucc/2;
P2 – sets the frequency;
P3– sets the waveform;
P4 – sets the hysteresis of the comparator (frequency and amplitude of the triangle-wave signal)
P5 – sets the amplification of the triangle-wave and sawtooth signals.

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Simple Baud Rate Generator Circuit Project

 This is a Simple Baud Rate Generator Circuit Project. In this article, an RC oscillator is used as a baud rate generator. If you can calibrate the frequency of such a circuit sufficiently accurately (within a few percent) using a frequency meter, it will work very well. However, it may well drift a bit after some time, and then…. Consequently, here we present a small crystal-controlled oscillator. If you start with a crystal frequency of 2.45765 MHz and divide it by multiples of 2, you can very nicely obtain the well-known baud rates of 9600, 4800, 2400, 600, 300, 150 and 75. If you look closely at this series, you will see that 1200 baud is missing, since divider in the 4060 has no Q10 output!

 Baud Rate Generator Circuit Diagram

If you do not need 1200 baud, this is not a problem. However, seeing that 1200 baud is used in practice more often than 600 baud, we have put a divide-by-two stage in the circuit after the 4060, in the form of a 74HC74 flip-flop. This yields a similar series of baud rates, in which 600 baud is missing. The trimmer is for the calibration purists; a 33 pF capacitor will usually provide sufficient accuracy. The current consumption of this circuit is very low (around 1mA), thanks to the use of CMOS components. 

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Subwoofer Lowpass Filter using uA741 Single Op-Amp Ic Project

This is the simplest Sub woofer Low Pass filter Circuit using uA741 single op amp ic. The circuit is very low cost with respect to their work. The cut off frequency of this circuit is 25Hz to 80Hz maximum. Using this circuit , you can easily design a 2.1 Sub-woofer Speaker System at your own Home. The circuit contains very few components.In Pakistan, the cost of this circuit with PCB is Rs:45 The same circuit is working in my own hand made sub-woofer system.

Parts List: 

R1,R3,R4 = 10K 1/4W
R2=100K 1/4W
CY1,CY2 = 0.22uF Polyester
C1,C2 = 10uF/25V Electrolytic
IC1 = uA741A Single Op-Amp Ic + 8 Pin Ic Socket
3 Pin Male & Female Connector x 2
2 Pin Male & Female Connector x 1
PCB as in required size 4.5 cm x 3.4 cm

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Micropower Crystal Oscillator Cicuit Diagram

Crystal oscillators for digital circuits are normally built as Pierce oscillators with an inverter.The inverter operates as a linear amplifier and thus requires extra current. But you can also build a crystal oscillator using an  operational amplifier (op amp for short)! If a  very low frequency is involved, for instance  32.768 kHz (commonly used for clocks), you can get away with a comparatively ‘slow’ micro power op amp. 

Micropower Crystal Oscillator Circuit Diagram

 

In the sample circuit shown a widely avail-able TLC271 is used. On pin 8 we have the  opportunity to set the ‘bias mode’, with three  choices ranging between fast operation with  higher current consumption and slower operation at low current. For our clock crystal the middle setting will suit us fine. Pin 8 is there-fore connected to the voltage divider R1/R2. The current consumption of the entire circuit  is impressively modest and at 5 V this is just  56 µA! The oscillator also functions astoundingly well at 3.3 V. At the same time the cur-rent drops to a more battery-friendly 41 µA. A  prototype built in the Elektor Labs produced  the slightly higher values indicated in the circuit diagram. 

The output signal delivered by this circuit has  admittedly scant similarity to a square wave.  Nevertheless some cosmetic surgery will tidy  this up, with treatment in the Schmitt trigger  following. To save current (naturally) we use  a CMOS device such as the 74HC14.

Sourced Be: Elektor

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