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269 Threads found on Oscillating
not interested in buying one already made. If you feel like experimenting, this is a simple method to turn 12VDC into 24VAC sinewaves. It combines: * full H-bridge * oscillating action through LC 2nd order butterworth configuration * automatic detection of resonant frequency * boosts supply voltage to a higher vol
Plotting the stability circles for the provided S-parameters of NE3210S01 can be seen that the transistor is potential unstable in 1GHz-7GHz frequency range. Making stable to use as an LNA perhaps is not a problem, but to make it stable and then to make it oscillating could be a
I am doing calculations on negative feedback oscillator. Here is some confusing part. If oscillation condition is met either at input or output port, then circuit is oscillating. I understand that. But when i calculate reflection coefficients for both cases, i get different matching networks. I thought that formula of Gout and Gin for both cases w
I Know a guy who built this exact circuit 35 years ago. His power supply works to this day. I got the schematic from him. Our layouts are different and I attribute this fact to mine oscillating and his not. All I know is that the circuit works. I visited him about a month ago and gave it a go. Flawless. Current limiting works great and stable. Bett
Audioguru, I think they mean a synchronous rectifier instead of self oscillating. Using a MOSFET as a synchronized switch to provide rectification. Brian.
how? because even though there are capacitors in your active filter, there is a non-zero DC gain of the circuit. WHEN the loop is locked, that DC gain is used to tune the VCO to keep it locked. The capacitors, to some extent, just help the loop from oscillating/ringing if a perturbation happens.
Sounds like you have build a nice oscillator with the segment or digit driver transistors. Long PCB traces are a prerequisite to make it oscillating. There's a problem in your circuit, not directly related to the "ringing" problem which should be fixed first. The npn transistor segment drivers are only partly turned on by the 3.3V base voltage. Sho
Hi, I'm trying to build a DC motor regulation circuit, however I'm having some trouble with getting my rotary encoder to work properly. I tested the encoder in a pretty simple manner: I hooked it up to my Arduino board, and monitored one of the encoder channels on my PC. The output of the channel was in a form of oscillating pulses while the encode
I am trying to simulate my PLL for the 3 different process corners. For the fast corner, I get a result as shown: 123279 Why is the Vcont (Control voltage driving the VCO) oscillating like this? It should lock at 40 Mhz or what could be the reason for the oscialltions? It works for the slow and typical corners b
The factory added input level pots to each channel of this stereo amp (a custom mod for the purchaser) when it was built years ago. Now one of the channels is oscillating. The oscillation affects the audio range and will vary somewhat in frequency and amplitude depending on the setting of the pot. I swapped pots between channels and all was well
Hi, I attached the schematic of a gated ring oscillator and its timing and phase diagram. Having had this figure I have two questions. First of all, can anybody describe the phase behavior of the gated ring oscillator? How does the oscillator start oscillating from the initial phase at the rising edge of input data? In fact I am interested
thermal effects in the transistor and varactor. Use a power transistor with a big flange, to get small thermal resistance, and just throttle it back like it was a small signal transistor. The varactor, decouple it as much as you can. Why not leave it all DC powered, but just snub the RF signal so it stops oscillating.
I'm learning HSPICE. When simulating a ring VCO, I can't get oscillating wave. It seems to be locked,but i'm sure the connection is right for the netlist is available on Cadence Spectre. Is there any issues. Thanks in advance.
Hello I have found this power pierce oscillator in an old magazine and I have tried it with sucess, using the 2n2166 which gave max output at 3.5W. I have also seen this circuit which is another type of oscillator that is used as a self oscillating mixer in receive mode. I was wondering is I c
For designed op-amp's enable circuit, step input results proper steady state output. But with pulse input, output is oscillating. Why so? Thanks.
Hey guys, Attached is the figure of a instumentation amplifier which I am trying to get to work. I am trying to amplify a 10MHz signal received by a 2uH center-tapped aircoil. Its running off a 9V battery and a reference voltage of 2.5 V (Vref) is generated by a general purpose op amp. Also an LDO provides a regulated 5V supply to the opamps (LM
The self-oscillating MOSFET inverter is a rather bad design, it's neither guranteed to oscillate at all nor to keep the transistor maximum ratings.
A bit simplified, the snubber capacitor is charged by a series circuit of resistor and leakage inductance. While R charging involves 0.5CV? losses, L charging is lossless (but oscillating). Varying the L/R ratio gives different fractions 0.5CV?.
AC supply probably has lots of 100Hz ripple. Measure it with no load and full load signal. Each power amp is probably oscillating above 100Khz causing overheating. If it gets hot with no load, put 2.7Ohm 0.47uF as indicated in specs or similar series snubber on each output to ground. If DC out is not matched at Vcc/2, offset the offending one wit
Some DROs not oscillating without metal plate placed above resonator. As i understand it is not frequency tuning (phase condition) problem, because moving resonator does not start oscillation. Although placing small metal piece above resonator instantly starts oscillation. What stands behind this? Less radiation because magnetic field lines stick t
I'm not suprised it doesn't work. The original circuit is self oscillating, L1 and L2 have to be on the same magnetic alignment and corectly orientated. In your circuit you: 1. overload the output of the micro because you omitted the base resistor in Q3 2. have the secondary coils connected to the base of Q1. It should either be the collector or t
You circuit must be unstable (oscillating)from feedback phase shift as 8.2v/11k is not the same as 0.3V/1k in output shared current. ... Edit.. What does scope say? And what is the total load ...caution wire capacitance and inductance in layout. 1k+1k? This is design does not bias FETs properly and seems poor in general. It may need AC load
Problem you have is when resistors are changed Ic current must not be changed. Resistor 1k can have so high resistance that 270ohm resistor is not needed. In this case temperature stability is lowest possible. Changing resistors you also change the gain and phase of amplifier which may stop oscillating. 10mA current of a divider is a bit high for Q
2SC4367 has a typical transit frequency of 1 GHz (min. 600 MHz), so you're lucky if the circuit is oscillating at 900 MHz at all. You all want to use transistor with GHz bandwidth instead. Apart from this point, what's the value of C2? Is your circuit layout suited for 900 MHz at all? If you connected an antenna, it's frequency dependent radi
What's your problem with the circuit, it's rather straightforward. 1. A self-oscillating flyback converter 2. A transistor to speed up switch-off operation The diode in parallel to the transistor is a zener (e.g. 12 V) that keeps the gate voltage constant over input voltage variations. From the options listed by xenos I would prefer the pho
Hello all I'm designing a Class E PA at 13.56MHz. I find that Freescale MRFE6VS25N, which can work from 1.8MHz to 2GHz, is very suitable for my design. However, the wide working bandwidth makes a new issue: Will the amplifier be oscillating due to the harmonics which are s
Is it oscillating with the brush motor? It may be that it is an underdamped oscillation near 75kHz with 5A current limit on ripple which can blow most caps except Polyester or Polyurethane film with low ESR. Since a 1R resistor is also in series to current limit these instabilities, the CAP ESR must be much less than 1R. THe driver is much lower
Since your x2 Op Amp has a bandwidth of around 1MHz driving a capacitive cable load plus termination, it could be oscillating and you are hearing the thermal noise in the output stage. Load the output with something like 0.1uF in series with 100 Ohms to ground ~ 50kHz Although the 220 Ohm series R ought to prevent this. So layout, decoupling e
an injection locked ring oscillator is NOT A PLL! so lets start there. how are u injecting the subharmonic? How are you removing the oscillating power? what are you doing to make the ring oscillator ONLY free run at the output frequency?
Hi, I have a PLL target running at 12.5GHz. Schematic top level works. Standalone post-layout VCO also works. But top level post-layout PLL simulation is not working. I've tried all the methods i can think of: 1. add initial condition at VCO outputs; 2. set max. step. 3. add a current pulse injection at one of VCO outputs; (4. i haven't tried
If I mount an oscillator in Orcad, as I know how often it is oscillating.
Stability is not considered in the band which is interested only, instead stability should be checked until fmax.Therefore, your LNA may work in the band but it may also oscillate somewhere at out of band. What type of pHEMT do you use ?? D-Type or E-Type ?? You LNA is probably oscillating somewhere but your don't know.I understand this from absolu
This isn't a very clever circuit - don't expect good results! I think the way it is supposed to work is Q1 is a weak oscillator, whether it oscillates or not depends on the setting of P1 and the coils proximity to something that might change it's inductance. If it starts oscillating, the signal it produces is rectified by the voltage doubler of D
An oscillator needs positive feedback. If it has only negative feedback then it is an amplifier, not an oscillator. The phase shift circuit in an oscillator has a certain amount of signal loss which must be made up by the gain of the circuit. A simulator does not know that noise is amplified and gets an oscillator to start oscillating. Then you mu
.....But from my circuit i think that pull up resistor (at output of opamp) make the output 4V while inputs are not given. Am I right ?? no. The comparator has an input offset voltage that could be positive, negative or zero so the output could be high or low or oscillating.
This are two cascaded first order filters which have real poles and can't show an oscillating step response by nature. Instead you'll want a second order filter with a complex pole pair. It can be implemented either as LC filter or as active filter with feedback. Some references are here You'll decide
All amplifers will contain contain noise in the bandwidth of the oscillator and even overtones of crystal oscillators. The harmonic with the highest gain will end up oscillating. Both input transients on power up and random noise contribute signal that gets filtered. In the case of a balanced oscillator with exactly unity loop gain at 0 or 360 de
LNA is showing same output what ever the input it has, it is not showing amplifying signal. Some LNA is showing negative gain, when -500mV appeared at the gate. I think your LNA is oscillating, at a frequency that you are not looking for...
Hello, I have here a simulation (LTspice) of a self oscillating Buck LED driver. It just regulates the LED current by switching ON/OFF its FET when the inductor current hits the requisite peak and trough levels. One comparator acts on the peak of the inductor current, the other, on the trough. (there is a resistive inductor current sensor)
I answered this for you in the other forum...... AN oscillating electric field creates AN oscillating magnetic field my bold added for clarity Yes that is correct ... but it goes further an oscillating electric field creates an oscillating magnetic field, which creates an oscillating electric (...)
Your simple buck regulators may be oscillating with insufficient load capacitance and low ESR for ripple or simply insufficient pre-load of 10% before the switch. Please advise if adding preload helps on stability and larger low ESR Cout Caps. - - - Updated - - - Your simple buck regulators may be oscilla
If you want a -regulated- high voltage output then you need all of the functionality of these integrated PWM regulators. If you need only rough, much higher voltage then simpler self-oscillating boosters could do. To make one of these have good regulation, especially dynamic and with safety features, would end up being more elaborate (to the board
I have just constructed the truxgraphics power supply but it just wont stop oscillating and it is gives a maximum voltage within 1v of the preset maximum CAN SOMEONE HELP
What do you see at the terminals when it stops working? Extremely long leads can bring you oscillation problems, consider the 3-wire bundle as a lousy tank and feedback. Just to pull decent DC curves from high frequency transistors on a ~10cm wire length fixture often required ferrite beads to keep the thing from oscillating. At 10 meters, bet on
Hi, I've got a a circuit with three cascaded LNAs (MGA-62563) and there is a lot of oscillation. I depopulated a LNA stage to simplify the problem to two LNAs but the oscillations still occur. The circuit is for GPS at 1.57542GHz, and I don't really care about wideband performance. The oscillation is at 1.573GHz at ~10dBm and then a harmon
If you used s-parameters for your coils, the problem can arise from them. HB does not like much s-parameters because they include some discontinuities between the frequency samples ( I have faced to face a similar oscillator was not oscillating with my EM simulated coil defined with its' s-parameters.When I have changed
I am not following you. Unless you connect some other circuit to multipin connector P1...NONE of the leds will ever light up. Explain what goes on on the other side of P1. It might be oscillating
David, The "N" simply indicates the type of package-DIP, in your case. Your circuit may very well be oscillating, but not a frequency that upsets your TV or radio. And I think you might want to connect your antenna (whatever it is) to pin 2 rather than where you have it, as it will affect your frequency since it's connected to the capacitor.
hello everyone, i'm having trouble with this the output of my 3 stage cmos rectifier is 0.4 with input vrf = 0.25V, then if i connect the rectifier to a non-overlapping and self-oscillating clock and a voltage doubler circuit the output of my rectifier becomes 0.16V and the final output of my voltage doubler is 0.5V..but if i change the rectifier
I agree with johnjoe, "source unleveled" is also a possible warning in case of oscillating amplifier.