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285 Threads found on Oscillating
It may be unstable and oscillating. Board layout and decoupling becomes critical with such fast slew rate amps. Remove any groundplane in a layout under the chip near inputs to prevent parasitic capacitive coupling and place decoupling caps very close to supply pins. Use at least a 10-100nF together with a low value electrolytic. Observe any minimu
Here is the simplified schema of a self-oscillating class D amplifier. anyone explain it to me how this circuit work. Maybe some intuitive approach help me understand this circuit.
hello every body I am using CDCE421 Clock generator IC for generating 50MHz clock.i am using a 33MHz quartz crystal as the clock input to the CDCE421 and i am using a 22pF as load capacitor for the input crystal.The major problem is that the input crystal is not oscillating.both the pins in the crystal goes to a low state when i am trying to se
hello, if an SMPS is unstable, does that mean it oscillates when it is on constant load, or does the oscillation only happen when there is a transient load change.? -i'd be so grateful for any reply
Hi, Yes. You are right. First flop may go in metastable condition. In this case, output will be unpredictable, it might be oscillating between some voltage levels, or it might be moving to some voltage level( i.e. either Vcc or Vss). While one use the synchronizer, one has to make sure that the first flip flop will resolved to some value(it can
Try to disconnect the input power (without load) to see if is oscillating. If you use input power and the current is going high without load, is possible to be due to high VSWR, which again is normal if the amplifier output match was designed for a specific load.
Could be oscillating and buring out, possibly operating into a poor load momentarily. Could be your positive power supply comes up before the negative gate supply turns on, and the device draws 10 amps for a short time and fries.
Hi, Most likely an oscillating amplifier, try putting a small capacititance across its feed back. Use tantalum electrlytic capacitor to bypass the power supply pins. Separate the ground return of the opamp and low input returns from power stages, connect them together and then connect to power supply negative point directly. Connect the retur
berryfan wrote: Enquiry: Re: help!some like oscillating.what's the it? thanks.I have used spectrum analyzer ,and the I see in 980M and 1.8G there can be signal changing between -40--50dbm.I think if it's a oscillation ,it can be one power.not changing so much.what do you think Your situation is clear. You have bat test setup and you are pickin
Hi. Kinetic watches have oscillating weights inside them which in turn are connected to an electrical generator. like this: If one was to scale this up, would it generate enough power to actually be useful for other appliances? say... a battery charger f
grittinjames, not sure how that circuit helps the OP. eem2am, you can find good information for feedback on some of ST's Flyback converters with 6561 application notes. They go into pole analysis in some detail. If you've got severe oscillating problems I would be looking at the resistive biasing of the feedback network to begin with - i
I think your LDO is oscillating. Generally device noise is smaller than this level.
This TV transmitter circuit should work fine, I remember I?ve built something similar years ago. The DC voltage on base of Q4 should be zero, because this works in Class C and the transistor is DC biased by the incoming RF signal. Check if Q3 is oscillating, looking for signal in UHF TV band. The DC supply in the collector of Q4 is AM modulated b
Seems that your circuit is oscillating around 60MHz. Try to change the input and the output match, use an RF choke instead R4, and try to avoid using that BPF at the output (LP input match and HP output match should be fine getting decent bandwidth).
If your feedback divider does not work, pll may fail to correct control voltage, and no feedback coming means the vco is not oscillating which moves control voltage to VDD. At the instance of strange behavior please check the output of the feedback divider. Regards.
When constructing a pll with veriloga, I got the vco control voltage like in the attachment. It seems to be oscillating periodically. Which block has problem according the vctrl waveform?
The tuning voltage applied to the well contacts (A-mode varactor) of the varactor controls the capacitance.The oscillating voltage of the output signal of the VCO appears at the gate of the varactor. can the gate of the varactor be connected to the tuning voltage? why? I think the parasitic of VCO will be increased if t
The comparator circuit should have a small amount of positive feedback for hysteresis to make the output have a snap action instead of oscillating at the threshold voltage. It should have a supply bypass capacitor.
If you want to say a self oscillating power supply then following document will help. (you need to change the single output to multiple outputs) ENJOY!
These loading capacitors should be as small as possible and not bigger than the maximum allowed by the crystal manufacturer. Any loading capacitors will cause higher drive currents through the crystal and affect long term accuracy in critical timing circuits. Naturally their value also alter the oscillating frequency slightly. Typical power dissipa
Eugen_E did an excellent job explaining how it works. I suggest you read his explanation a few more times. If your interested in this circuit, you may wish to also look at the Royer Converter which is used commonly in energy conversion. Self oscillating converters are the basis for many important electronic circuits. Its well worth investin
this means that the LNA is oscillating , negative S11 means that the LNA is not stable , u need to check the stability factor of the LNA , and check source and load stability circils khouly
I cascade two stages of UPC2776 as a post amplifier to boost the signal from a Transimpedance amplifier. Since UPC2776 have 23dB gain and 2.7GHz bandwidth and TIA supposed to work at 70MHz, it should not be problem from bandwidth point of view. The wired thing happened once I power up UPC 2776. Output of the second stage oscillating very badly
If the PA dies without source and load connected means that is oscillating, which is not very unusual in these conditions. You have to tune first the input match for best input return loss (S11) using low input power. Check for out-of-band high gain that could degenerate in oscillations at high output power, and/or poor load. After that
Ceramic resonators are made of high-stability piezoelectric ceramics, generally lead zirconium titanate (PZT) which functions as a mechanical resonator. When voltage is applied, its piezoelectric "vibration behavior" causes an oscillating signal. The thickness of the ceramic substrate determines the resonance frequency of the device. A ceramic r
Hi, I use a LM317T to build a current regulator 60mA. 15VDC Input (Pin 2) 680nF to ground. Output (Pin 3) 20 Ohms to Ref (Pin 1). Usually the circuit works fine. But with a new LM317T from ST (China) it's oscillating 1..10MHz and I found no solution to solve the Problem.
You can go ahead and try, but I predict it will STOP oscillating if you put a capacitor across Q2 (C-E)!
Simultaneously oscillating at two non-harmonically related frequencies. Check the latest issue of MW Journal:
I want to redo this article: ?Dynamical Electric and Magnetic Metamaterial Response at Terahertz Frequencies? but I have find a big problem in the value of S11 and S21. I plot the S parameter which oscillating up and down. According to article, the sample is a planar array of SRRs fabricated upon semi-insulating gallium arsenide substrate (A plan
oscillator has no input and produces a oscillating wave as output... inverter has an input and the output is just the inversion of the input....
This circuit is a positive circuit if you analyze it carefully, so in order to make it not oscillating, you have to make the loop gain less than one.
hi! i build a pll voltage domain model with veriloga,and it works.then i replace the vco with a real circuit of transistors while the others remains implemented by veriloga.the linear process is basiclly the same.but if zooming out the waveform,we will find the voltage is always oscillating hidding in the linear process,and the control voltage d
Guys need you!!! I need articles or links regarding RCC or self oscillating flyback converter. Hope you'll provide one. I need it badly thanks a lot. rgds, your friendly neighborhood
Since it is an FM transmitter, the modulation is FM, but also a little AM. T2 forms a Colpitts oscillator, with the oscillating frequency depending on the LC components, but also on the internal capacitances of the transistor. The transistor capacitances are dependent on the DC bias point, and since the modulating signals alters the T2 bias, resul
i want a 12 v 1a smps . with single transister . anybody having cuircuit of self oscilating one without feedback
The self-oscillating flyback you find in disposable cameras should do the trick. You cannot get cheaper than that. It uses a single transistor and a few other inexpensive parts, plus the transformer, which is needed regardless of the final solution.
regarding a ring vco, am i right in thinking the oscillating frequency is inversely proportional to the number of stages? what difference will it make having 15 stages compared to having 5 stages?
For any closed-loop system, you need to simulate the stability, or you need to know at know, it's stable or oscillating according your requirement.
I use pss+pnoise to do VCO simulation. I set the beat frequency at the oscillating frequency from tran simulation. When I change the beat frequency to the frequency from PSS, the phase noise change worse. So which should be the right beat frequency and right phase noise? Thanks!
One method would be to measure using a frequency counter and a scope. If you don?t have this devices probably the simplest method to see only if is oscillating is to use a simple diode detector and a meter.
Very simple. A jumper wire of thickness 0.8mm, 10mm long, core copper, can provide 10nH between two solder pads. To create 22nH, simple make it 20mm long and coil a turn or two. However, this can be lossy. So you can use glue to melt around it to reduce loss and prevent it from oscillating (that can create some audible noise like "hissing")
Dear all, What is the minimum value of the crystal oscillators that is available in the market. I want ot use it for frequency counter. Regards, Nikhilesh:D
In the realm of sound reinforcement (as in public address systems and loudspeakers), electric hum is often caused by induction. This hum is generated by oscillating electric currents induced in sensitive (high gain) audio circuitry by the alternating electromagnetic fields emanating from nearby mains-powered devices like power transformers.
Hi, I think that you may have incorrect or non-accurate transistor model, which results a non-oscillating circuit to modulate. :D
In the design of SOA, the oscillating frequency is variant by the input signal amplitude .I want to know how to stabilize the frequency,could anybody give me an instruction?
In simple systems, the oscillator is directly connected to the antenna. In those, if you present the wrong antenna impedance the oscillator stops oscillating. You might have one of those.
Well, I always just think of the resonator/active device as a pair of microwave black boxes with S parameters. If the reflection coefficient of the ring resonator is 0.6, for instance, I know that if I hook up an active device with a reflection coefficient of 1.7 and the right phase angle, it has a chance of oscillating. Set up your feedback on t
2N3904 is a 100MHz transistor. and it is almost impossible to oscillate at 1.27GHz. One thing could happen. The circuit is oscillating somewhere close to 100MHz, and if you are using a frequency counter to measure the frequency, for some reasons this one is picking up the 12 harmonic. Sound craz
what's the difference between hspice 2004 and hspice 2005? who can tell me? in the transient simulation of a circuit, the output is oscillating if i uses hspice 2004. if i use hspice 2005, the output will be stable. and in the ac loop simulation, the output is always stable in hspice 2004 and 2005. why it happens?
Hi, I've built a guitar amp using the schematics on this site It is mostly working fine, but when i flick the 'bright' switch, the opamp goes into oscillation. I've bypassed both power pins to ground with 0.1uF ceramics, and I've tried it with the power amp disconnected, so it's definetely got somethi