Search Engine www.edaboard.com

251 Threads found on edaboard.com: Oscillating
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.
...they Also use Comparators without the Stablization capacitor because the WANT the comparator to Oscillate, Why would anyone want a comparator to oscillate? what does it do when it's oscillating? it's at a frequency In a simplified viewpoint Comparators are designed to operate at open-loop circuits or
Phase shift circuit when output phase is 180 degree has gain 1/29. Conditions for oscillating are satisfied when amplifier gain is 29 minimum. Gain we are talking depends on type of phase shift circuit.
Hysteresis prevents a Schmitt trigger from oscillating when a slowly changing input voltage is near the input threshold voltage. A Schmitt trigger can convert a sinewave input into a squarewave or rectangular wave output with fast rise and fall times. A Schmitt trigger can give a logic output when its input voltage is slowly changing.
It is oscillating at out of band.
It is for sure an overtone crystal. This means that the crystal is ct at 1/3 of the oscillating frequency, but if you select the proper harminic, it will oscillate three times the natural frequancy. Due to parasitics, the natural frequency is not exactely 1/3 of the overtone frequency. Mandi
Your circuit does not show its supply voltage (24V?) and frequency of the PWM. The 1N4007 diode is extremely slow (designed for rectifying 50Hz). Use a fast diode. It is missing the important low value resistors in series with the gates of the Mosfets that prevent them from oscillating (which makes them hot).
I made "mood lights" with an oscillating fader circuit made with a dual opamp and an output transistor. Three of these circuits drive red, green and blue LEDs. The oscillator frequencies are all a little different so that the three colors add "randomly" and produce millions of colors including pure white and darkness. Your waveform has square-wave
If you measure the difference in frequency between the spurious outputs, this is the frequency at which it is oscillating. This will give you a clue as where your problem is. If its very low frequency then its bias or power supply, if its RF (IF) then its a RF decoupling problem. Frank I have an ultra low nois
Don't stumple upon your sloppy usage of technical terms. Lagging power factor hasn't to do with "negative power". Reactive power is just oscillating energy, no net power is transferred from or to the load.
Medical - Power RF - DIY -> Do not know how? Sounds like a dangerous combination. Doing something like this require basic RF knowledge both theoretical and that you is familiar with instruments to measure and verify if you have designed a 40 MHz/10 Watt amplifier and not a self-oscillating harmonic generator. Even a smaller design mistake and a suc
The lousy old LM741 opamps are probably oscillating at 15kHz (built on a breadboard?). A heartbeat is at a very low frequency. Your circuit has two lowpass filters that eliminate 15kHz and other high audio frequencies.
The opamp has such a high gain that when the circuit is built on a breadboard then it oscillates. When oscillating, its output is switching high and low at a high frequency. Your multimeter is measuring the average DC output voltage which is near half the supply voltage. Usually, a comparator circuit has hysteresis (a little positive feedback) so
R5 is loading down R4, C4 so that it does not begin oscillating. Add another opamp to buffer R4, C4 and drive the output.
well, either u are dividing the 10 MHz reference down by 2 somewhere in the chip, or u have an oscillating op amp somewhere.
yeah it is possible, but even if out of band, will probably not have too much loss. more likely your oscillator stops oscillating with the load u have. Try a short length of straight waveguide between the two to see if it works then.
With the inverting input shorted to output the opamp is probably oscillating. This will make it get warm but shouldn't kill it as it has thermal protection. You would need to check with a high bandwidth oscilloscope as it will be around 400MHz. I would probably either use a fast opamp to drive a MOSFET or a MOSFET driver IC driving a MOSFET. Ano
It may not oscillating...you have to probe the output .. n check o/p frequency on might amplifing input noise..
Without knowing your circuit, we can hardly determine why it's "oscillating".