285 Threads found on edaboard.com: Oscillating
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
Analog Circuit Design :: 06-05-2015 19:44 :: FvM :: Replies: 15 :: Views: 1266
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
RF, Microwave, Antennas and Optics :: 05-04-2015 09:13 :: torbai :: Replies: 0 :: Views: 460
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
Analog Circuit Design :: 04-22-2015 03:34 :: SunnySkyguy :: Replies: 11 :: Views: 1305
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
Analog Circuit Design :: 03-18-2015 03:02 :: SunnySkyguy :: Replies: 8 :: Views: 795
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?
RF, Microwave, Antennas and Optics :: 03-15-2015 15:01 :: biff44 :: Replies: 1 :: Views: 737
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
RF, Microwave, Antennas and Optics :: 03-07-2015 08:30 :: prcken :: Replies: 7 :: Views: 1074
If I mount an oscillator in Orcad, as I know how often it is oscillating.
Analog Circuit Design :: 03-02-2015 18:28 :: eletmoraes :: Replies: 0 :: Views: 445
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
RF, Microwave, Antennas and Optics :: 02-12-2015 14:01 :: BigBoss :: Replies: 13 :: Views: 791
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
Analog Circuit Design :: 01-25-2015 22:17 :: betwixt :: Replies: 3 :: Views: 704
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
Analog Circuit Design :: 01-08-2015 18:12 :: Audioguru :: Replies: 3 :: Views: 767
.....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.
Analog Circuit Design :: 12-03-2014 16:52 :: Audioguru :: Replies: 5 :: Views: 2315
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
Analog Circuit Design :: 11-01-2014 09:40 :: FvM :: Replies: 5 :: Views: 1567
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
Elementary Electronic Questions :: 09-16-2014 21:45 :: SunnySkyguy :: Replies: 13 :: Views: 833
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...
RF, Microwave, Antennas and Optics :: 09-13-2014 14:54 :: vfone :: Replies: 32 :: Views: 2811
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)
Power Electronics :: 07-06-2014 10:24 :: treez :: Replies: 8 :: Views: 976
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 (...)
RF, Microwave, Antennas and Optics :: 06-19-2014 12:02 :: davenn :: Replies: 3 :: Views: 991
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
Power Electronics :: 06-04-2014 13:59 :: SunnySkyguy :: Replies: 5 :: Views: 1126
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
Analog Circuit Design :: 04-25-2014 20:09 :: dick_freebird :: Replies: 17 :: Views: 4364
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
Microcontrollers :: 04-17-2014 17:42 :: m.ngoni :: Replies: 0 :: Views: 706
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
Analog Integrated Circuit (IC) Design, Layout and Fabrication :: 04-05-2014 02:44 :: dick_freebird :: Replies: 3 :: Views: 710