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Questions tagged [oscillation]

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2answers
61 views

Load capacitance of crystal

I know this question has been asked many times before, however this question differs in the use of an uneven set of capacitors. I'm replacing the crystal on an old computer. The original symptoms ...
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0answers
89 views

LM358 Headphone Amplifier Oscillations

I'm trying to build a very simple headphone amplifier for my bass guitar. The bass has a built-in amplifier, meaning that unity-gain is sufficient for my amplifier, I essentially only need a voltage ...
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0answers
21 views

Oscillating boost converter output voltage that has a differential amplifier for load, in DRV8662 piezo actuator driver IC

I am building a circuit to drive a piezo stack in a pulsatile fashion and I am using the DRV8662 piezo driver from TI to do so. The circuit diagram is shown here (please disregard the several ...
3
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1answer
49 views

Active filter - oscillation and incorrect operation

I have a noisy and low amplitude (0-50mV amplitude) signal from a hall effect sensor (TI DRV5053) that has a ~1V DC offset. The signal will be in the range of 95-105 Hz and is used to determine the ...
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1answer
55 views

Trying to have NMOSs in parallel while passing current through only one at a time

If I wanted to have a bias current I1 going through M1 or M2 and I want M1 to alternate between on off (M1 on/M2 off, M1 off/M2 on) would this work? I simulated this with spice and for the first ...
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1answer
50 views

Can oscillations happen even if negative feedback is present?

By OPAMP book says that virtual short is applicable in OPAMP only if negative feedback is present an output is not oscillating.I don't get how oscillations can occur at output if the feedback is ...
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0answers
49 views

Making sure power is supplied from a DPS5020 fast enough for an induction board to oscillate

Apologies in advance - I'm a software guy who likes to dabble here and there and my latest project is a little beyond the comfort zone. I'm building an induction heater (with off-the-shelf parts for ...
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2answers
2k views

This op-amp buffer is oscillating and I can't figure out why

Currently, this is the only assembled part on the circuit board. This is a simple inverting buffer circuit that should be at the input. The op-amp (LTC6241HV) is powered +/-5V from a linear bench ...
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3answers
353 views

Opamp + NPN and MOSFET in the feedback network, how to prevent oscillations

Background The task is to add an electronic means to limit the power applied to an electric motor in an industrial setting. The operator normally controls the motor power through a lever that is ...
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2answers
100 views

Deliyannis-type narrowband filter is oscillating when I apply GND to the input

TLTR: My Deliyannis-type narrowband filter is oscillating when I apply GND to the input Vin. I was expecting to get almost zero volts, but I am actually getting a sine wave at almost 20KHz. I´m trying ...
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1answer
84 views

Simple way to create a disturbance on DC power

First of all, i must say that I am a software engineer, with very-low to no experience in circuits designs, and a very rudimentary understanding of electrical engineering and circuits. 101 really. ...
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4answers
595 views

Constant current source with MOSFET, OPAMP and Instrument Amp

UPDATE Based on the information from everyone answering below, I have modified my circuit and the oscillation has completely vanished! I started performing small modifications in order of easiest to ...
0
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1answer
53 views

LM2776 is it normal to have the oscillations in “bursts”

Is it normal LM2776 to oscillate in "bursts": The frequency of the oscillation is OK, but they come in the 8 oscillation bursts every ~9us. Is it normal? The board design and the schematic is ...
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2answers
204 views

PA92 OPAMP phase compensation

I'm having trouble to understand the phase compensation on the PA92 opamp. First I'll explain quickly the circuit I'm building.   1.  The circuit I'm using a 200V battery and would like ...
2
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1answer
99 views

Driving a difficult load with an Op-Amp: high capacitance, high current, high speed

I've been banging my head against this problem all day. I have a bizarre load that I need to drive over 88 feet of SMA that is a 68 ohm pullup to 15V. The cabling adds 2.64 nF of capacitance. I've ...
5
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3answers
468 views

Kickstarting an opamp for oscillating?

I have been building many different variations of op-amp oscillators but have come across a recurring issue that has manifested itself again in this VCO schematic: I find that when turning on my ...
2
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1answer
105 views

Quartz Clock Accuracy

Do the vibrations of aircraft engines (or any engine, for that matter) dilute the accuracy of a quartz clock? I haven't done any kind of research or hypothesis testing, though I believe that the ...
1
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2answers
491 views

Op amp driving a LED oscillates, how to stabilize?

I have a simple LED driver circuit like this: simulate this circuit – Schematic created using CircuitLab The op-amp is OPA354 250-MHz, Rail-to-Rail I/O, CMOS Operational Amplifier supplied ...
0
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2answers
83 views

Why exactly a RLC Circuit powered by DC oscillates?

First sorry if the question is stupid... I am learning. I am trying to visualize here, without equations, what happens to a RLC circuit that makes it oscillate. Consider a RLC circuit, a switch and ...
6
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2answers
364 views

5.5 kHz noise on SMPS output

I am designing a low noise SMPS like this http://www.ti.com/lit/df/tidrgc2/tidrgc2.pdf switching from 40-90 kHz. I have a weird problem, on the output we are seeing a spike of noise at 5.5 kHz and ...
0
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1answer
32 views

Can a bilateral switch block transmitter interference and can my board still produce great audio?

I made a circuit in which an ISD1760 chip outputs music via an LM386 IC and I like the quality and volume of sound, however, when I run an HM-TRP transmitter on the same circuit board and the ...
0
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1answer
75 views

High Frequency Excitation on Class D Amplifier

I'm building a discretized class D audio amplifier that's running at 250kHz that's designed to run on a single ended 80V supply. I was seeing very high amplitude, high frequency excitations on the ...
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3answers
103 views

LM2664 noise in the OPAMPS output signal. How to remove

I have 4 opamps powered from the LM2664. Two of them (1MHZ 1.6V R-R) are preparing the offset voltage for the pair of the OPA4141 which actually provide the signal for the ADC It works as expected ...
3
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5answers
2k views

How to calculate the frequency of oscillation of this low-pass phase shift oscillator?

In the following phase-shift oscillator a low pass network is used instead of a high-pass network. simulate this circuit – Schematic created using CircuitLab Usually the frequency of ...
0
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1answer
250 views

Why is my relay oscillating for over a half-second?

I'm building a circuit that can turn on a relay when the variable resistor cools down. Its operating principle is cooling down the variable resistor increases its resistance, causing the voltage at ...
2
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1answer
236 views

AC analysis of a oscillator

This question relates to my previous question. I am interested in deriving an analytical relationship for the oscillation frequency of this oscillator. As the first step, I have initiated the ...
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1answer
236 views

How do i get this constant current circuit stable?

Im making a battery tester / discharger. For this i'm using a constant current circuit made with an opamp and a mosfet. I built and tested the circuit by itself with around 3-4A and it was stable. I ...
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2answers
225 views

How to DC bias the output of a Wien Bridge oscillator so that it oscillates about 2V?

I was wondering what a practical method of biasing the output would be so that it osicllates around 2V? I tried connecting an DC voltage source in parallel to the positive terminal but alas the output ...
0
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2answers
159 views

Opamp Voltage Follower Oscilates

I am trying to measure voltage across a 0.1R shunt resistor. When i measure voltage between input1 and input2 with multimeter i can see 10 mili volts. When i connect input1 to a voltage follower in ...
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2answers
841 views

Op Amp Oscillation BPW34 Radiation detection

I have build the following circuit on a stripboard Now the problem is, even if I do not have the BPW34 diode attached my output shows a nice sqaure wave as you can see here But I have no idea where ...
0
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1answer
187 views

Wien Bridge Oscillator

So I built the Wien bridge oscillator without automatic gain control and I am using a preset to tune the circuit instead. My question is this, so when I reduce the gain of the op-amp to something ...
1
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2answers
50 views

Instant signal frequency change on amplifier

I was wondering what happens to an amplifier when the frequency is suddenly changed from (in my case) 2401 MHz to 2479 MHz. Would the amplifier somehow oscillate at the beginning or would it be steady?...
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0answers
92 views

self-quenched oscillator

I am trying to simulate a circuit which is composed of an oscillator which oscillates and reaches a maximum oscillation amplitude, then there's a peak detector that is following the peak of ...
1
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1answer
99 views

Negative-Gm Oscillator Biasing Conditions

I have some questions regarding the circuit below. I need to ensure two conditions are met. The output is taken from the drains of the cross-coupled pair. I think the drain voltages (1.198V) are not ...
0
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1answer
44 views

regions in cadence

I have a circuit that in it mosfets go through different regions (the circuits's core is an oscillator, I quench my oscillator by some mechanism and then let it oscillate again till the amplitude of ...
1
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1answer
91 views

Oscillation in digital circuits?

When designing analog circuits with feedback loops, attention must be paid to concepts such as gain and phase margin, open-loop gain, closed-loop gain, etc. in order to prevent oscillations (if you're ...
0
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1answer
79 views

Voltage regulator position

Hello if unregulated power supply (transformer, bridge and main caps) is 30 cm away from the circuit to feed, is it better to put the voltage regulator close to the circuit (long input and short ...
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0answers
230 views

Opamp + FET oscillate in voltage regulator for inductive load

I'm currently trying to regulate the voltage on an inductive load. The idea is to use an opamp to divide the actual voltage across the coil down, compare it to a set voltage and drive a FET so that ...
3
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2answers
136 views

Simple Constant Current Circuit Acting Strange on Occasion

I have a simple constant current source driven by a DAC. Very low frequency, less than 100 Hz changes on the input. I have had trouble once in a while when the transistor either fails or temporarily ...
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1answer
292 views

Some questions about a magnetically coupled circuit

Below the RLC circuit on the left side by the help of a periodic impulse generator V1 generates periodic damped oscillations with a certain frequency, and the resulting oscillating current couples to ...
2
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1answer
195 views

High freq OP-AMP voltage follower is ringing and is unstable

I try to design analog buffer for the 5MSPS STM32 ADC. I try to use TSH114IDT or CLC4007 opamps ( I need 8 in total). I have done so far: Tried the design below with or without some of the elements - ...
0
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1answer
202 views

How can I correct instability in a push-pull transistor amplifier?

In our EE lab, we had to build the following amplifier. It is from this lab manual, page 40. A week ago, I built it successfully, with 2n3904/3906 and d44vh10/ d45vh10 for the power amplifiers (Q3,...
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4answers
727 views

Problem with opamp stability in DC load

I'm trying to make DC load up to 20A with 1mA precision. Current sense resistor is 5mΩ, so the voltage on this current sense will be from 5μV to 100mV. I picked LTC2050HV (datasheet) which have very ...
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0answers
164 views

Why does this resistor avoid this oscillation?

I am learning the effects of diodes going trough ON to OFF (so that I can see the consumption of these kind of power supplies) and, when it comes to simulate the circuit, I dont understand why if I ...
3
votes
1answer
848 views

Strange oscillations with TL431 voltage reference

I have a problem with TL431 voltage reference circuit: There is no load connected to VREF25. When I remove C8, voltage VREF25 is perfectly stable 2.5V. But when I put C8 back into the circuit, ...
8
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2answers
747 views

Is it possible for an opamp to oscillate at a frequency greater than its GBP?

I was installing a tl3141 into a headphone amplifier circuit and it appears to break into ~250mVp-p oscillation at 8-10MHz on the lower half of the waveform when fed a 1kHz sine wave. Is that even ...
1
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4answers
188 views

Capacitance on the output of an op amp

I have read a lot about capacitive loads on the output of an op-amp and the possibility of unwanted oscillations and instability. my knowledge on phase margin and frequency domain analysis is a little ...
2
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1answer
135 views

Optical isolator (VO0600T) circuit not working

I have a circuit where a 3.3 V DATA signal is optically isolated using the VO0600T IC. The circuit is as follows: In the schematic, VEE = 5 V (pin 8). Note that there are 2 separate grounds on either ...
3
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2answers
465 views

NE5532 strange oscillations

I am designing a small audio amp and am experiencing some weird oscillations in the first OPamp (NE5532), wich is setup as a noninverting amp. The amp is supplied with +-20V and has 100nf bypass ...
2
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0answers
452 views

Crystal Oscillator Design and “Crystal Drive Level”

I followed the video at the link http://www.analogzoo.com/2015/07/ . The video directs watchers to a tool at http://www.analogzoo.com/lab/pierce_bjt.html to help determine parameters to cause ...