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Questions tagged [oscillator]

A device or circuit that generates an AC signal at a certain frequency.

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Can this oscillator possibly work?

I am trying to build a crude RF oscillator. My first attempt, though it simulated fine, disappointingly did not oscillate when soldered together. So, to debug this, I reduced the simulation example ...
bobuhito's user avatar
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3 votes
4 answers
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Does PLL stabilize the frequency variations of a crystal oscillator?

I don't know inner workings of phased locked loop and only know that PLL can be used to multiply the clock frequency of a crystal oscillator for instance for a micro-controller. My question is: does ...
user4444's user avatar
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Why my RC-oscillator design does not produce any output?

I designed this single transistor RC-oscillator circuit and implemented it on the breadboard. However, I detect no oscillations on the output. I know that using power transistor is not the best idea ...
ScienceDiscoverer's user avatar
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Wien bridge oscillates at 6x expected freq and amplitude oscillates too

A while ago I made a Wien bridge oscillator to go from ~500 Hz to ~1 MHz, using an NE5532 opamp and stabilizing amplitude with the typical opposing diodes method. Worked fine, but the output was too ...
Hal Gee's user avatar
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Are these filters suitable for this application?

I want to use the ADF4350 as a local oscillator and I want it to sweep as fast as possible from a start frequency A to the end frequency B the issue is the span is large and for that i have to use a ...
Tintin's user avatar
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3 answers
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Why do some JFETs oscillate and others don't?

Below is a simple JFET Clapp Oscillator, which works quite well. It starts oscillating at around 40us and gets into clean, stable oscillation by 100us: When I replace the J309 JFET with a more ...
SRobertJames's user avatar
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PCB microprocessor 16MHz oscillator layout feedback

I thought I'd give an update to the changes I've made for my 2 layer PCB regarding the 16MHz crystal oscillator that I've added. Yes, this is a continuation of PCB layout for 16 MHz crystal oscillator....
hdaniu's user avatar
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PCB layout for 16 MHz crystal oscillator

I'm barely getting started with PCB designing. I'm working on my dissertation project and I want to develop a PCB board with an integrated microcontroller (ATmega2560-16AU) and some motor drivers as ...
hdaniu's user avatar
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Are inductors in resonant circuits dangerous? They produce very high voltages

A simple series LC resonant circuit has theoretically infinite voltage in the middle between L and C, if we assume 0 ESR and exact resonant frequency: \$V_{at LC junc} = V_{in} \frac{X_{C1}}{X_{C1}-...
SRobertJames's user avatar
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2 votes
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Will a circuit oscillate at all its resonance modes or only the most dominant one?

Will a circuit oscillate at all its resonance modes or only the most dominant one? Consider an amplifier with a feedback loop that meets the Barkhausen criteria at multiple frequencies. Will it ...
SRobertJames's user avatar
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How can this Clapp JFET oscillate when its gate is tied to ground at the resonance frequency?

How does the circuit below oscillate? It seems to have |gain| < 1 at its oscillation frequency of 2.25 MHz, yet it oscillates there. My analysis: The DC path is through L4 only, allowing a bias ...
SRobertJames's user avatar
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Where is the phase shift on this oscillator?

I didn't think the oscillator below could work, but I built it, and it does: I used 10 uH for the inductor, 2.7 nF for the capacitor, and got oscillations around 8 MHz. The feedback loop is a series ...
SRobertJames's user avatar
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What is the oscillator in this 433MHz transmitter?

I took this image from ev1527 datasheet. The RF transistor drives the tank circuit to generate rf signal. What is the name of this rf oscillator? Is it a Colpits oscillator? Also there is a project in ...
Zaki's user avatar
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What does the standard deviation of TIE measurement tell me about my clock signal jitter?

When we take a Time Interval Error (TIE) measurement of a clock signal, we are presented with two measurement outputs, the mean error and the standard deviation. When I measured the TIE of a 32....
tronhawk's user avatar
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What requirements of a feedback network are needed to produce oscillation?

I'm trying to understand how to analyze simple oscillators, and would like to know if my conclusions about the required feedback network are correct: The simplest way to build an oscillator is with: ...
SRobertJames's user avatar
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Why does the voltage increase when I connect this amplifier to a gate driver?

I'm trying to breadboard a simple circuit testing a TI UC3708N gate driver, which I need to drive from an AWG square wave. Since the AWG has limited amplitude (and perhaps limited current), I made ...
SRobertJames's user avatar
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Oscillator phase noise effects

The usual complications of phase noise in a practical system that I see mentioned are: If the RF input of a mixer contains an interferer close to the desired signal, then the interferer mixes with ...
Halleff's user avatar
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4 answers
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Explain how this crystal oscillator works

Help me to understand how this oscillator works. Although I mostly want the vintage computer to work, I also want to understand how this circuit functions. I attempted to recreate the oscillator on a ...
ndemarco's user avatar
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1 answer
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Why does this simple op amp create an AM modulated envelope over its carrier?

The circuit below is an ideal op amp (requires no power, can produce any output voltage) in LTSpice: LTSpice shows it amplifying the 159.155 kHZ input, as expected. But it also shows a 2500 kHz AM ...
SRobertJames's user avatar
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Use of crystal oscillator ‎ ‎

Can I use this crystal oscillator instead of the crystal in this picture? ESP8266 Hardware Design Guidelines If so, can you explain to me how, I have to connect the crystal?
Frederik's user avatar
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Are \$v_{C}\$ and \$v_{L}\$ in phase in an LC oscillator?

Looking at these figures, I can't help but to conclude that \$v_{C}\$ and \$v_{L}\$ are in phase! Why? Well, because \$v_{C}=q/c\$ I know this is wrong but why? Reference: https://shorturl.at/30NEu
Jack's user avatar
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making a DF96 pentode crystal oscillator

I want to make a crystal oscillator using DF96 vacuum tube. The tube is a small RF/IF amplifier for battery operated systems. This tube is unique in the sense that it only takes 25ma of filament ...
Ashok Das's user avatar
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HCMOS Oscillator output waveform measurement fault

My ASV-50.000MHZ-EJ-T oscillator's datasheet is here . My goal is to measure the oscillator output with an oscilloscope. The ideal square waveform I expect is as follows, my measurement setup ...
Electronx's user avatar
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Why does the LC oscillator work according to the scheme with a common base?

I study HF oscillators and i stuck. I put build the following circuit: The waveform: A question arises. Why does this work at all, because the input resistance of the circuit is extremely low. In ...
Станислав Тимошко's user avatar
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How is the gain of this CS stage (gmRo)^2 in this oscillator?

I was reading this paper which uses MEMS active mode resonant fin transistors for making a mmWave Oscillator. I came upon this schematic for the proposed oscillator in the paper, which says that the ...
Koustubh Jain's user avatar
2 votes
1 answer
61 views

MachXO2 VHDL Internal Oscillator - "ERROR: formal nom_freq is not declared"

I am trying to run the code below, but I get an error on line generic map(NOM_FREQ => "2.56"); and I am very confused why. The error says "ERROR - ...
jukebox41188's user avatar
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1 answer
48 views

Lattice MachXO3LF FPGA Internal Clock Accuracy

On the data sheet for the Lattice MachXO3 FPGA family, it shows that the internal oscillator has varying nominal frequencies with +/- 5% accuracy. Does this apply to its entire temperature range ...
user373900's user avatar
2 votes
1 answer
117 views

LTspice and ngspice simulation results differ by 5-6GHz

I simulated a basic CMOS inverter based 3 stage ring oscillator in both LTspice and ngspice, using the same model files (using NCSU's freepdk45 models (VTG slow slow corner)). I expected there to be ...
Koustubh Jain's user avatar
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1 answer
86 views

Feed output of oscillator to a 50 ohm load

I have a 30 MHz colpitts oscillator whose output I want to feed into a 50 ohm input impedance amplifier. When I try to simulate it the oscillator works fine by itself, however when I connect a 50 ohm ...
Francisco Maggi's user avatar
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"When doubling the width and length of the MOSFET in a ring oscillator, the output frequency decreases. What could be the cause?"

"After conducting simulations, I found that doubling both the width and length of the PMOS (210n, 45n) and NMOS (120n, 45n) transistors resulted in a decrease in the output frequency. It's ...
cocoromina's user avatar
2 votes
2 answers
129 views

Simple doorbell circuit using transistors

This is a circuit diagram for constructing a simple doorbell circuit using transistors. Can anyone see a fault in the circuit? I've tried it on a breadboard and the circuit works with the buzzer as a ...
Monde Albevar's user avatar
1 vote
0 answers
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How can a ring oscillator's frequency be inversely proportional to supply voltage?

I was reading this paper on Ring Oscillators, when I came across the following statement on the first page : since the delay of an inverter falls as the supply voltage \$V_{DD}\$ increases, the ...
Koustubh Jain's user avatar
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2 answers
89 views

Voltage Controlled Amplifier using Oscillator

I have found an example of a voltage Controlled amplifier using a square wave control on this page I'm trying to modify it using my own control signal, a triangle wave from Low frequency oscillator. ...
miguelfuzz's user avatar
1 vote
2 answers
136 views

How to use this crystal oscillator? [closed]

I recently bought a 315Mhz crystal oscillator off of Amazon but I can’t figure out how to use it nor can I find any information online about it. The only thing I can find on them is that picture. I ...
Marcus Marchese's user avatar
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3 answers
76 views

Adding reference voltage to oscillator

I have designed a very basic Schmitt Trigger LFO. However, the power supply for the op amp has to be 9 and 0 V instead of 9 and -9V. For doing so, i supose that i need to add some voltage reference ...
miguelfuzz's user avatar
1 vote
2 answers
60 views

Role of the load resistors in an astable multivibrator

I am currently trying to wrap my head around astable multivibrators. I want to design a circuit that oscilates at about 1 kHz. The formula I am using to determine the values for the base resistors (I ...
balu's user avatar
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2 votes
2 answers
103 views

Improving the waveshape and amplitude of a saw-tooth generator

I am a student in in college level physics and so I do not have a lot of knowledge when it comes to circuits and the different electrical components. Still, as a project, I decided to try to build an ...
Boldumus's user avatar
1 vote
1 answer
126 views

Recommendation for sine wave of 100kHz with 1ppm stable amplitude

I need to design a 100 kHz sine wave with 1 ppm stable amplitude. I mean the noise of the amplitude should be lower than 1 ppm RMS and also the thermal stability should be < 1 pmm/K. I was thinking ...
Chris's user avatar
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7 votes
6 answers
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Ethernet port as a signal generator

I was wondering if it's possible to turn a PC into a signal generator through the ethernet port (or at least an amplitude-modulated sine generator). I specifically care about the ethernet port since ...
KKZiomek's user avatar
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0 votes
2 answers
137 views

Generating a clear sinusoidal wave through the oscillator to generate the "Ding Dong" sound

I am working on a project to try to recreate a close replica of the "Ding Dong" doorbell sound. I have yet to make the decay. (I would definitely appreciate if you have tips for that.) I am ...
user369928's user avatar
6 votes
2 answers
391 views

Why is the frequency and voltage of my Colpitts oscillator lower on breadboard than LTSpice?

My colpitts oscillator I made on LTSpice oscillated at 5 MHz at a peak-to-peak voltage of 260V. When I put all the components down on my breadboard and measured it with a real oscilloscope, the ...
george_2roz's user avatar
2 votes
2 answers
123 views

Why do the diodes make a huge difference in an RC sinewave generator circuit?

In the following LTspice simulation of a sine wave generator circuit, it cannot oscillate without D1 and D2, but as long as D1 and D2 are added, (1+R5/R6)=1.5 can also oscillate (as shown in the ...
谢一鸣's user avatar
0 votes
1 answer
77 views

The effect of input and output impedance

This picture shows the classical feedback system and this assumption about this system. "the input impedances of both the amplifier and the feedback network are infinite and their output ...
Serkan Kaya's user avatar
1 vote
2 answers
88 views

Comparator Using Common Gate CMOS

I am currently in the process of designing and testing a CMOS Comparator based of a Common Gate Topology. Below is an extract of the ref circuit I am using: The authors in the paper mention "...
soccernismo's user avatar
0 votes
1 answer
45 views

Subthreshold Operation for Beta Multiplier Circuit

I am currently in the process of designing a Beta Multiplier Circuit using 120 nm technology, and want to run the circuit in subthreshold operation with (Vgs < 4*Vthermal). Below are some captures ...
soccernismo's user avatar
0 votes
1 answer
72 views

What is the rule for continuous oscillation of an RF circuit with integrated LC?

Circuit simulation software helps out many times from hard mathematical formulas. I designed most of the RF circuits with the help of LTS and Proteus. I have seen that they are good equally, but have ...
user avatar
5 votes
2 answers
348 views

PIC MCU wont accept external oscillator

I have been trying to use a PIC16F684 with an external oscillator. I tried a few, changed capacitors, added series resistor - nothing. Right now I have a 10 MHz crystal connected with 30 pF capacitors ...
Ri Di's user avatar
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0 votes
5 answers
184 views

How do the capacitor & resistor actually introduce a delay in the following oscillating circuit in terms of direct current?

simulate this circuit – Schematic created using CircuitLab How, in terms of direct current, do the capacitor and resistor actually create the delay and still permit the oscillation given that DC ...
J R's user avatar
  • 93
1 vote
1 answer
65 views

555 Circuit for Spark Gap Lighter Not Functioning Correctly

I have a circuit designed and fabricated with the following schematic: The specific 555 timer I'm using is a NE555DR. However, when under power the circuit doesn't appear to oscillate and no spark ...
Charles Dean Modrich's user avatar
2 votes
2 answers
83 views

Importance of load capacitance in 32.765 kHz crystals

I am designing a very low power portable device that has an RTC and I cannot choose a crystal for it. Most crystals on the market have 12.5pF load capacitance, however there are also 6 or 4pF crystals ...
Archimedes's user avatar

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