Questions tagged [oscillator]

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

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24 views

Discrete MOSFET with bulk pin [on hold]

everyone. I have a research project about oscillators and I have to buy MOSFET with bulk pin(both NMOS and PMOS). Is there anywhere that I can buy this rare(!!!) component?? I really need your bits ...
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45 views

Crystal oscillator frequency measurement disturbance

I've been building a 10 MHz crystal oscillator circuit (Pierce configuration) followed by a frequency mixer attached to it. The oscillator circuit and mixer are powered by an ordinary power supply. I ...
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642 views

Crystal Oscillators in MCU

let's consider a MCU (for instance ATMEGA328) with a crystal. I know that the electrical model of a crystal is this one: My question is: which is the circuit that makes it oscillate? I do not see it ...
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41 views

RC phase shift oscillator

An RC phase shift oscillator is a sine wave generator. It only needs a DC power source. No input is provided for circuit. What is happening inside the RC phase shift oscillator? How is a sine wave ...
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90 views

Why aren't quartz crystals' pin pitch aligned to the inch grid? [closed]

This is most probably stupid question, but I would love hearing the story. Can not find anything relevant in the net. The spacing between the pins of HC-49 is 4.88 mm, there're some other variations ...
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61 views

Measuring the quality factor RLC circuit

I am trying to get the Q factor for this circuit but I don't know how to simulate it properly. I did a frequency sweep from 1 Hz - 30 MHz. The oscillating frequency is 16 MHz. I can't get the ...
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43 views

Oscillator configuration for PIC24F proteus

I'm trying to simulate a PIC24FJ in proteus for the most realistic way but even tough proteus is running the simulation it doesn't allow me to configure HS or XT oscillator for primary oscillator ...
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1answer
44 views

Filttering noise out from high frequency 1MHz oscilator (Teslacoil driver)

I have a 74HCT14N based ''RC'' square-wave oscillator. The produced signal then goes to PMIC gate-driver and finally to a mosfet which drives the primary coil at resonant frequency. (about 930-1000kHz)...
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52 views

wien bridge oscillator transfer function

I am trying to calculate the transfer function of a wien bridge oscillator but there is something wrong in my calculations. In the picture below there are my results from this calcultation. I am ...
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1answer
57 views

Astable Multivibrator - Kalafuna is burning, not switching

I am having problems with circuit, that I designed. R1=R2=R3=R4= 680 ohm; C1=C2 = 20nF; R5=R6 = 7,3kohm Circuit works only when voltage is about 0,5-0,7V and resistors r5/r6 are not connected. It "...
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34 views

different threshold value of 2 inverters

What is the meaning of having 2 series inverters, one with the switching threshold at 1.025 V and the other with the threshold at 0.3V? What does this difference between the switching levels mean? ...
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1answer
33 views

quartz crystal - figure of merit

What represents this formula in terms of an RLC series circuit that forms a resonator? It is called figure of merit and it is defined like this: M = 1/ w*C1*R1 where w = 2*pi*f
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52 views

figure of merit for oscillators

Can someone explain to me what means figure of merit in terms of an oscillator? There is no explanation online related to this.
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170 views

Discrete component FM radio receiver circuit - explanation needed

I have built an FM radio receiver from a kit. I'm very happy with the results! It is the Sinclair Micro FM. My goal is to learn about discrete electronics (NO IC's.) The radio works great, but I ...
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3answers
73 views

Selecting a damping resistor for crystal oscillator circuit

I'm building a data acquisition board with an ADAR7251 ADC. I'm trying to figure out the crystal oscillator circuit, and am stuck on the damping resistor. The relevant datasheet is https://www.analog....
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1answer
56 views

How is oscillation condition fulfilled in this oscillator circuit?

I'm rather curious as to how oscillating conditions are achieved in this oscillator. My attempt at an analysis follows. The BJT is operating in common base mode. As the base resistors are equal, the ...
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94 views

Minimoog oscillator LTSpice simulation problem

I am running a simulation on the Moog Minimoog Model D oscillator in LTSpice. The circuit with the models needed is attached below. The square wave and triangular wave generation work as expected. ...
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1answer
35 views

VDD on crystal oscillator to GND or +3.3V? (ESP8266EX)

Currently I'm trying to make a circuit for the ESP8266EX Chip and I've stumbled across the "Crystal Oscillator" - section. It's said that the ESP8266EX supports 40MHz, 26MHz and 24MHz crystal ...
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100 views

Power efficient oscillator topologies?

I'm building an oscillator for a battery powered capacitive position sensor and I need it to have a high swing (>800 mV) at the output while keeping power consumption low enough. I'm feeding the ...
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3answers
110 views

How to design a circuit that creates high electric field between two conducting plates?

I need to create an electric field of about ~1500V to move electrically charged particles in a container. I'm trying to convert a 9V DC battery to an AC signal using a crystal oscillator and then ...
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37 views

Design and simulation of cross coupled oscillator in ADS

I am currently designing a low power consumption and low phase noise VCO in ADS. But while performing the transient response I'm not getting the oscillating waveform in the output. I have attached the ...
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5answers
2k views

Astable 555 circuit not oscillating

I'm a complete beginner to electronics, but I'm trying to follow Ben Eaters video series "Building an 8-bit computer". I tried to do the first part of an astable 555 timer, but the LED does not ...
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1answer
66 views

7404 NOT gate LC oscillator

I have found this 7404 LC oscilator schematic online. How does it work? I know that you can connect the input and out of a NOT gate and it will oscillate at a very high freq, dependant on parasitics ...
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2answers
78 views

1v square wave generator

I'm trying to create a square wave form from a single AA battery, say 1v. I came across an IC which is essentially a low voltage 555 timer: Semtech SX8122 however it is marked obsolete. I would like ...
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52 views

Why does the frequency of an oscillator changes with the time duration of .TRAN command?

I have simulated an oscillator circuit using OTA in SPICE. It is a self starting oscillator. However, the frequency of oscillation does not change with the bias current but changes with the duration ...
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1answer
66 views

dsPIC primary oscillator works for a few seconds or clock doesn't switch

I'm using a dsPIC33EP512MC806 and can't get the primary oscillator to work. The internal works fine, but if I switch to the primary it either hangs on Clock switch or goes in to the ...
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3answers
53 views

Relaxation oscillator, how to change the duty cycle

I have a Relaxation Oscillator here. What I'm trying to do is to change the duty cycle of ca 50% to 10%. What I thought of and tried to change R1 and C1 values so the time the capacitor loads and ...
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1answer
46 views

555 timer that does not output low when reset

I'm trying to design a circuit with the following goals: When not active, output can be either Vcc or floating When triggered by pressing a button, output pulses several times to GND at some ...
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2answers
42 views

Clock Generation from Oscillator

Is there specific standard ways to generate clocks from oscillators? Referring to generating a square-wave clock from a sinusoidal oscillator output. I can think of a few circuits involving diodes as ...
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67 views

Clapp oscillator PCB not working when ground pin is connected

I have designed a Clapp oscillator working at 25MHz. The catch is I designed the circuit to be a part of frequency compensation network. So, I incorporated a few reverse-biased varactors whose ...
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2answers
135 views

Why do the center tapped capacitors in Colpitts oscillator give an inversion?

In Colpitts oscillator, we have two capacitors in series, with the middle grounded. It is said in explanations that in this way, the signal from the output of the amplifier is phase shifted 180 ...
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72 views

How does an op-amp work without proper power supply?

I have built a chua's circuit following this diagram: Source: Kennedy 92(pdf). The rectangle inside NR is and eight pin dual opamp. Then, I remove the 9V battery on the right. It is replaced by a ...
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86 views

Capacitance divider of Colpitts Oscillator

For the following Colpitts Oscillator, Why does employing the capacitance divider up-converts the source impedance of transistor by a factor of (1+C2/C1)2
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1answer
83 views

Calculating Rs Value for 32kHz Pierce-Gate Crystal Oscillator Circuit

Edit: My primary objective is to learn the mathematical model to compute the load resistor \$R_s\$ to satisfy a given crystal's drive level, not just fixing the one instance below. I'm building a ...
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1answer
58 views

Colpitts oscillator: how to reduce amplitude thermal drift?

I have built this circuit, supply ±12V: I am using a LM6172 amplifier. I have found the transfer function of the filter involved: \$H(j\omega)=\frac{1}{1 + \frac{R_3}{R_1} - L\omega^2(C_2+C_1\frac{...
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1answer
87 views

Simple frequency-tunable spark generator?

This may sound weird, but... I am attempting to design a steampunk / gothic horror-styled electric harpsichord, with sparkgaps as the sound source in the vein of musical Tesla coils. Unlike musical ...
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54 views

Colpitts / Clapp oscillator crystal drive level

simulate this circuit – Schematic created using CircuitLab As I understand this circuit has some initial gain at startup, then as the oscillation builds up gain goes to unity at some moment. ...
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44 views

Clapp Oscillator Oscillating Frequency Strongly Dependent on the Transistor

For temperature sensing purposes, I have been challenging myself to design a dual mode crystal oscillator operating at the frequencies 30MHz and 90MHz (fundamental tone and the third overtone, ...
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3answers
101 views

Colpitts oscillator : having trouble while respecting Barkhausen criterion, is this criterion insufficient there?

I'm trying to simulate a Colpitts oscillator. I've determined transfer function of the low-pass filter of this circuit: I reached this expression: \$H(j\omega)=\frac{1}{1-LC_2\omega^2+jR_3\omega(C_2+...
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72 views

Can I replace the transistor in this circuit (Esaki oscillator) with a Zener diode?

Can I replace the transistor in this circuit (Esaki oscillator) with a Zener diode?
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1answer
51 views

Fundamental CMOS astable multivibrator

So i need to perform analysis of simple astable multivibrator circuit shown in the following picture: These Vdd and GND are just the power rails of those CMOS inverters. Now, i need to perform ...
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43 views

Load capacitance of the crystal: what is the practical difference between devices?

There's a lot of info and guides on how to select and calculate load capacitors for the parallel resonant circuits. They all assume that people do already possess crystal, and know its CL. That CL ...
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68 views

PCB Layout - Ground Plane Clearance Around and Under Ceramic Resonator

We are using Murata's 4MHz Ceramic Resonator (CSTCR4M00G53-R0) in one of our designs and request help in PCB layout design around Ceramic Resonator. The below Murata's FAQs page suggests not to place ...
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1answer
37 views

How is Q for surface acoustic wave devices measured?

I do not have a good understanding of Q, the quality factor. I get the basic concept that it has to do with energy losses within a system, particularly oscillating systems like resonators. Higher Q ...
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3answers
132 views

JFET stabilised wien bridge component ratios

I find myself in need of a sine wave oscillator and have decided on the wien bridge. I have followed all the tutorials but have a few questions that do not seem to be answered elsewhere. Firstly, I ...
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1answer
39 views

What is the difference between residual phase noise and absolute phase noise?

Studying the characteristics of an oscillator with a phase noise analyzer, but I don't quite understand the difference between absolute and residual noise. Any help would be greatly appreciated
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65 views

VCO circuit Analysis

can you help me with the basic comprehension of this Voltage Controlled Oscillator scheme (it was used in a PLL)? I do not understand why there are two varactors instead of one, and the role of the ...
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60 views

Is the difference in trace lengths why my RTC isnt working?

I am using the PCF8523TS RTC with a 32.768 kHz Crystal. I have tested the smaller package which worked fine with the Adafruit module, but I can't seem to get it to work with the TS package. I either ...
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42 views

Quartz Crystal and Resonance Frequencies

Let's consider this equivalent electrical model of a crystal: The evaluation of its series self resonance frequency is quite simple: it is sufficient to impose that the reactance of L1 is equal and ...
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63 views

Transformer and MOSFET combination not working

I am working to understand the circuit of a vibrating needle used in factories to scratch a mark on a soft surface. Essentially, this circuit drives a MOSFET bridge which then drives a Transformer. ...