# Tagged Questions

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

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### PIC32MX can't get 80 MHz Clock from Internal RC OSC

I am using PIC32MX795F512L with the internal RC oscillator. By changing the settings of the config, I can get to 60 MHz max. But I can't get to 80 MHz. When I change the config for 80&#...
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### What's the difference between all of the Atmega328p clocking options?

Reading through the data sheet of Atmel's Atmega328p microcontroller, I had heard reference of an internal 127kHz RC oscillator. This being the default oscillator if no external crystal/resonator was ...
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### 555 Oscillator with Steering Diodes

Based on the picture below, and the values of R1, R2, R3, and C1, how would one calculate the: A. Duty cycle B. Frequency of this 555 Oscillator? Diodes D1 and D2 are exactly identical.
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### Oscillator not running

I designed a board and sent it to China to have the PCB made and parts assembled. It contains an ARM CPU and a Micrel physical ethernet chip. I used a FOX Oscillator FXO-HC536R-25 (25 MHz) to ...
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### Mathmatically analizing different voltages in a phase changing circuit

I am trying to understand a phase shift oscillator from a mathematical perspective, and to begin I simply took the phase-shifting part of the circuit and am now trying to analyze the voltages as a ...
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### Voice Coil/ Solenoid driver

I am trying to figure out how to drive a solenoid/voice coil at 3V and 400-1000mA with a reciprocating output (forwards and reverse current) at around 50Hz as cheaply as possible. I have built some ...
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### Barkhausen criteria: which is the overall effect if only the magnitude criterion is met?

I am going to try to explain better my question. Considering a simple control scheme made up of a forward-path amplification$A$ and a feedback-path frequency dependent attenuation $\beta(j\omega)$...
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### Generation of sine waves within the audible range using a DAC

I am trying to generate up to 20 khz sine wave with the TLC5615 DAC but have only been able to obtain a maximum of 100 hz. I am using a 20 MHZ atmega328 MCU to transfer the required 16 bits (2 padding,...
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### External Oscillator [closed]

I am trying to receive clock by external oscillator. I have my own PCB with ATSAM4SD32CA. XIN and XOUT are connected to external oscillator (16MHz). Im try to do that on Keil uvision. I tryed to ...
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### MOSFET connection within oscillating circuit

I'm working on a group project, where for one part of the circuitry we have a "Royer Oscillator", which can be turned on/off via an N-channel MOSFET (IRFU4105ZPBF) at the input (whose gate is ...
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### Phase lock loop frequency of reference signal

I am writing a Matlab code for phase locked loop and up to now I assumed that frequency of input signal is given (known) and I choose frequency of my VCO close or exactly the same as reference signal. ...
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### Trying to understand the working principle of a weird transformer driver / oscillator

I'm trying to fix the high-voltage power supply of an old scope. The HV transformer is burnt, and I'm trying to replace it with a similar one (EPC19 core), but I'm failing. I already know how to wind ...
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### How the two Colpitts oscillators work?

I have just seen two Colpitts oscillators from the page as below. However, the page is not written in English. I tried to translate it into English but I could not understand it. Could anyone ...
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### What is the most energy effecient type of RF oscillator?

Here are the options: the Gunn Diode, the Barkhausen-Kurz Tube(AKA "transmitting triode"), the so-called Lighthouse Tube, the cavity Magnetron, the reflex Klystron. I'm leaving out the Gyrotron ...
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### Is it a bad idea to switch from using a quartz oscillator for my timing circuit to using a MEMS oscillator? [closed]

I've read MEMS oscillators offer improved performance including phase jitter less than 500fs and frequency stability down to +-0.1ppm. It's difficult to switch from quartz because it simply works and ...
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### I found what looks like a crystal oscillator with an xdl stamp I haven't seen before

I found an old transmitter with a crystal oscillator on it, when I looked at this I saw that it had "xdl 17.734475m" stamped onto it, I've only ever seen oscillators with just their frequency written ...
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### 250-350 MHz voltage controlled oscillator

I need to build a 250-350 MHz voltage controlled oscillator. I have been checking out ring oscillators but they cannot reach these frequencies (max ~20 MHz). Thus, I would like to know which are the ...
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### How sine wave is generated in wien bridge oscillator? [closed]

It is known that the initial feedback signal is developed from the noise in the resitors and the transients of the power supply. The question here is : why the waveform at the output is sine wave ...
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### Relaxation oscillator with two time constants

I have the following circuit and I have to find the duty cycle of the output signal and its frequency: I figured out that if $v_{cond} > 0$, then D4 will be forward biased and D3 reverse ...
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### What kind of oscillator is this circuit?(processor oscillator)

I was just seeing the datasheet of a motherboard and saw this oscillator circuit: What kind of oscillator is this circuit? what are the usage of those resistors? As you can see it has two input ...
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### LC tank Q factor

I am working on parallel LC tank. It is Rp // Lp // C . Rp = Rs( 1 + Q^2 ) Since inductor dominates capacitor under high frequency, Rs is parasitic resistance of inductor. It seems to me Q factor ...
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### About using a crystal as notch filter

I am looking to create a high q passive notch filter using a crystal. I am not very familiar with crystals, hoping that someone who's had a similar experience can enlighten. I know crystals are mostly ...
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### Peculiar voltage spikes in triangular waveform generator circuit

I recently made a triangular waveform generator circuit using LM324 op amp. But the output of the generator had some sort of periodic spikes in it. However I was able to suppress the spikes by ...
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### ATmega328 external crystal capacitor requirements

I am reading this guide and it states that, in order to use an external 16 MHz crystal for an ATmega328, I need two 22 pF capacitors. I found this bundle of two 20 pF capacitors and the crystal (sold ...
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### Voltage input values for Si550 voltage controlled oscillator?

I am trying to find the required voltage input for a particular Mhz frequency output, I chose a voltage controlled oscillator to allow for user over/under clocking. Datasheet, I probably missed ...
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### voltage controlled oscillator

Given below is a VCO circuit. Can anyone explain how the components work (especially the resistors and capacitors) and why the resistor and capacitor values are selected so. and what are the values to ...
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### Design of audio playback system

I'm having trouble understanding some concepts: In a complete audio playback system the out put of the DAC is connected directly to the input of the low-pass filter, and the output of the low-pass ...
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### Strange behavior on transformer driver

I'm trying to make a circuit to drive a transformer from a PWM signal produced by an AVR MCU. Here's the schematic: The MCU output in fact has 2 complimentary PWMs feeding two transistor pairs. For ...
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### How LTC3108-1's oscillator work?

I am reading about LTC3108-1 on the page. There is one part about oscillator that I am not sure how it works. Could anyone explain it more detail? Or could you give me a link so I can read up? ...
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### RC Relaxation Oscillator Problems

I found a schematic for this oscillator online here and I tried it, but instead of the LED turning on and off sawtooth style, it got brighter slowly, and stayed bright without getting dimmer. What is ...
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I found this circuit online: I found explanation on how a radio transmitter works in this site: http://www.dummies.com/how-to/content/radio-electronics-transmitters-and-receivers.html However, I am ...
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### Wien Bridge Oscillator with LM358

I am constructing 10kHz , 30kHz and 50kHz sine waves using wien bridge oscillator design with LM358 OP-Amp. I have a few problems with the circuits that i could not figure out. Thank you for all your ...
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### How does this oscillator work under a constant DC voltage?

Consider: How does the oscillator in this circuit work? A tank circuit can't oscillate when there is a constant DC voltage, am I wrong? I simulated the circuit in NI Multisim and couldn't observe ...
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### FCC Specialized Oscillator - for low frequency exemption

According to the FCC: The following devices are subject only to the general conditions of operation in §§15.5 [Dealing with certification] and 15.29 [Dealing with power] and are exempt from the ...
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### Transistor Use In Oscillator Design [closed]

Need to know how to actually make the transistor 2N3055 turn on and off at a set frequency to implement its use as an Oscillator. that is the Main event that I do not know. Given this information then ...
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### Clock Oscillator - Topology and PCB Layout recommendations

I'm designing one of my first layouts and I've read a lot of articles and StackExchange questions about guidelines and recommendations. It's a university project realized by another student that I ...
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### colpitts oscillator with jFET not working

I decided to build a colpitts oscillator using a jFET (2N3819): It seems to work fine @ http://www.falstad.com/circuit/ but when i try to build this circuit it does not work, any ideas? Thank you ...
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### Effect on opamp lead length for non-functional wien bridge oscillator

I've built two diode stabilised variable frequency wien bridge oscillator circuits according to this schematic: (source). Both are on the same stripboard and connect to a single LM324. One of the ...
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### How do I design an antenna in desired frequency with preset equivalent circuit model?

I am working on a project that an oscillator drives 1 mH inductor in 7.5 KHz. This oscillator also happens to be very efficient. However, I am constrained with inductor value. So, to make my design ...
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### Why doesn't this transistor circuit work as expected?

This is a circuit I have designed to work as an oscillator. But it doesn't work. The way I supposed this works: When power is ON, the capacitor(C1) starts charging through 1Kohm resistor. Once it ...
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### RC oscillator ageing

I know that a crystal oscillator has a particular ageing curve, that shall be taken into account when designing a long-term application. But what about the RC internal to the MCUs? I did not find ...
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### Sawtooth VCO and current source for modular synthesizer

I have been working on a current source and sawtooth core VCO based on the Electronotes/Aaron Lanterman/Ian Fritz designs/ideas. I have breadboarded out the attached VCO schematic; the transistors ...
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### resonator or Crystal Oscillator for atmega2560

I've received the PCB that I have designed. This PCB has an atmega2560 on it. I have designed it to use a Crystal Oscillator such as this figure shows : Is this designed supposed to work on an ...
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### How to find the resonant frequency of a human body?

I've read that the human body has resonant frequencies somewhere around 50MHz. I also think it would be interesting to look for values in other ranges like 10-100 kHz. I'm wondering how to build a ...
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### How to balance between frequency and duty cycle in this circuit?

I have this astable circuit that generate square waves with independent control of frequency and duty cycle: For this circuit: $$t_H=0.759\,C\,(R_f+R_y)$$ $$t_L=0.759\,C\,R_x$$ period = 0.759\,...
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### How to improve the full bridge / half bridge start up time?

I am trying to find out a way to improve the rise /start up time of a series LC circuit placed in a full bridge (or half bridge) circuit. Here is a simplified schematic. The circuit works very well, ...
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### LC Oscillator Gain Compression

I am designing an LC Colpits common base Oscillator for the FM broadcast band. The project is going to be extremely low radiated power as I will only be using it in my car. I am currently using this ...
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### Output impedance of an oscillator

I'm using a 27MHz oscillator and trying to measure its voltage level and waveform with oscilloscope. But I have no idea how to match the impedance of oscillator and oscilloscope, since the data sheet ...