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# Flicker

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258 Threads found on edaboard.com: Flicker

## Boost PFC LED electrolytic capacitors..not possible?

I look at it this way. With no large energy storage (electrolytic capacitors) your LEDs will always be dissipating the instantaneous input power, which will be sinusoidal at twice the line frequency. So you will get high ripple current and possibly visible flicker. You might also have more difficulty dealing with mains transients if it's a simple b

## N-path filters & their flicker noise of clock generation

Hi guys. I'm a master student. I designed a receiver using N-path filters for filtering & mixing input signals. For driving the N-path filter switches, we need to design a clock genefration with 1/N % duty-cycle. But in the total noise of receiver, we observe flicker noise of clock generation elements & it's significant. How do I decrease it???

## Is this LED current ripple going to be visible as flicker?

Do you mean power-line flicker or just LED flicker? In both cases I'd say "no" but I assume you want to have proofs. May be these links well be helpful:

## VCO phase noise error !

In fact the Noise Floor is weird and there isn't any flicker Noise corner or 1/fx drops directly If you post your simulation setup, we can interpret it better.

## How to stabilize ADC using PIC

As Klaus explained, if you have a fixed threshold there will always be 'flicker' as it is crossed, even if you do averaging first. The averaging takes out variations due to noise and measurement consistency but if the result is still a fixed value, there will be a problem with the exact point it is exceeded. You need to adjust the thresholds (eith

## Triac leakage current with LED light

There is a mathematical solution, if you are interested , by computing impedance of LEDs and caps. Also LEDs would benefit with a diode bridge after the triac to give DC instead of half wave rectified by LEDs to reduce flicker when on. LIght dimmers often flicker on LED lamps not designed for this and need a small tungsten night light or load

## [moved] Query about VU meters (led bargraph)

The LM3914 is a linear voltmeter but the LM3915 is better for measuring the logarithmic relationship of loudness with our hearing. My circuit uses a peak detector and its LEDs do not flicker, they show the exact levels of sounds. With no sound all my LEDs are off. With loud sounds all my LEDs are on at the same brightness. Half levels cause half th

## Flicker noise simulation for Schottky diodes

Hello everyone, I am trying to simulate the noise of a Schottky diode power detector. Theoretically, the flicker noise should approach zero if there is no dc bias but the simulation results I am getting using ADS are quite the contrary. Any comments and experiences are welcome. PS: I am attaching the plot of Id and output noise vs the DC bias v

## AC 3 phase voltage measuring circuit

Look guys neutral is only at earth potential at the supply transformer. Elsewhere it can be anything, though under normal conditions, its the I X R drop on the out of balance current causing a problem. We used to have a 6V bulb connected from N-E and it would flicker all the time and some times burn out. Frank

## Kf value in flicker noise calculation

I want to calculate a simple CS amplifier flicker noise. The parameters for flicker noise calculation are Cox, W , L , freq and Kf. Other flicker noise constant Kf , i had remaining values. What is the value fot Kf ?

## AC current direction Measuring circuit

To know the inverter power (magnitude and direction), you'll multiply and voltage and current (instantaneous power) and average the product. Under circumstances, it's sufficient to form sign(P) = sign(V) xor sign (I), needs only two comparators. The inverter can also "source" or "sink" reactive power, in this case sign (P) will flicker with doub

## Problem with fluttering relay

It is normal for a lamp to flicker on and off at double the mains frequency for long fluorescent tube lamps or at around 38kHz for compact fluorescent light bulbs. You must smooth the on-off fluctuations from the IR detector with a filter.

## Voltage feed back control loop

If you operate your inverter with constant load, there won't be any flicker. So apparently you are creating a problem with your approach rather than solving it. First step to understand the system behavior would be to run a control characteristic without feedback to verify that the duty cycle variation is working correctly. Secondly verify that

## LG 60pk550, thin vertical lines on screen.

I would like to know whether Horizontal lines are similarly caused. My LCD tv has horizontal lines that flicker and vibrate vertically as if the tv has lost vertical sync. The pictures and sound will be ok. But this flickering is much less when there is no signal. Only a little when there is the tv logo and a blue screen... Any Ideas?

You have some strange delays in that program. It would be better to balance the timing so all the digits get equal time slots and equal spacing. You flicker is probably due to the slow down in the program while it performs long checking routines: if(timer == 100) { d0++; timer=0; if(d0>=10) { d0=0; d1++; if(d1>=10) {

## Effect of buffer flicker noise in Voltage controlled oscillators

Hi, This is second post on this forum. I am trying to understand contribution of buffer in the phase noise of LC VCO in any CMOS process especially at the low offset frequencies (1/f? region). When one adds a buffer with the VCO core and simulate phase noise at both VCO output and the buffer output, the phase noise at the far offsets starts de

## DOT matrix flickering problem/incomplete character

Don't know what the "segment delay" value actually is, but there should be no problem to run the code in real hardware without flicker. In case you are talking about flickering in the proteus simulation, I suspect a pure simulation problem. Adjust the timeout in the LED display properties.

## Understanding of the Beat Signal of the Radar

HI, I am confused about the beat signal of the radar when I read some IEEE papers. I have the following questions: 1. What is the purpose of the beat signal? To avoid flicker noise? 2. Beat signal only fit for LFMCW radar? 3. How to conduct beat signal in Radar? Is it the 1/T, T is the period of the waveform? 4. Based

## [Moved]: Problems in simulation noise of amplifier

Probably the bandwidth of your opamp is smaller than flicker noise corner frequency?

## Measurement of mains flicker IEC61000-3-11

Hi, I'm talking about flicker, not Harmonics. IEC6100-3-3, IEC6100-3-2 refers to Harmonics I think....it's minefield. Rob.

## Flicker Noise Noise Folding Question

flicker noise is infinite at DC. Speaking properly, what tends to infinity in the flicker noise model is its power spectral density. If I pass flicker noise through an on/off switch with switching frequency w, what the output spectrum would be? Would the spectrum be infinite at w, 3*w, 5*w?etc? It doe

## HP8565A NO frequency Display

Hi, I need some help. I have an HP8565A and I have no Frequency readout neither on the CRT nor on the LED readout. The problem started a few months ago when the LED readout started to flicker and display intermittent lighting of the segments. Now it just displays 0.0000 I checked the 10V reference and is within tolerance. All voltages on the

## Problem with row scanning of led matrix

If the said delay is per row, 10 ms is surely too slow, 1 ms (= about 80 Hz refresh frequency) should be suffcient for flicker-free operation. To be sure that we are talking about the same thing, you should better describe the row and column signal sequence. May there something wrong.

## LED pilot light connected to 120 vac

The average current in the LED is (120V - 2V)/10k ohms divided by 2= 6mA which is not bright. It will flicker at 30Hz due to the diode. The LED will heat with about 0.012W and the 10k resistor will heat with 0.7W (it is way overloaded).

## Linear interpolation

Good morning, i wrote a simple text file as "noise file name" for a Vdc (analogLib) in cadence. When i plot the PSD, the first region (flicker noise region) is characterized by "humps, because of a non linear interpolation, i suppose. How can i select a linear interpolation for these point? Thank you! Dario

## Flicker noise and frequency relationship

Hi There is more detailed explanations telling about flicker Noise and It is inversely proportional to frequency. And they described about the reasons of flicker Noise.They are talking about crystal defects and DC current and recombination process also they are talking about memory of a circuit that is charge trapping in the semiconductor ma

## Help for VCO phase noise simulation after bandpass filter by using functional block

According to Leeson phase noise equation, doubling the loaded-Q the phase noise gets 6dB better. Try to use Q of 100 instead of 50, and see what happen. At least you find if the reason is the low Q filter added to the circuit. Beware that Leeson equation applies only between 1/f flicker corner and the corner where the white (flat) noise starts.

## Choosing a transistor for wideband amplifier

It will work but it will not able to satistfy the specifications ( especially NF because FETs have higher flicker Noise compare to Bipolars) as above 50MHz.If your amplifier will work 5kHz, I don't recommend you to use FETs because their NF problems under 50-100MHz.Why don't you consider Biploar ? NXP,Avago,Infineon,CEL and Renesas have very wide b

## Help me with Max7219 code.

I am sending the same float value (adc value) to MAX7219 Display function but the decimal points seems to flicker Do you mean the dot point is flicking alternating at wrong positions or is it just blinking at the same position ?

Phase Noise id principally dominated by Quality Factor of the Tank Circuit in MW Oscillators regarding to Linear Phase Noise approximation of Leeson.There are obviously other noise related parameters such as NF, flicker Noise corner frequency,Voltage Swing,OP Current etc. but Q factor is essentially dominant. An accurate and robust optimization tec

## Why increase transistor area will decrease flicker noise?

... how it comes if we increase the area of transistor can reduce flicker noise? This is only valid for constant drain current, and under sole consideration of the carrier density fluctuation (McWhorter) model, i.e. not considering other models like the mobility fluctuation (Hooge) or the c

## The "Flicker" parametrization interface

This one is almost trivial... To parametrize/configure simple DIY boards powered by small 8-bit microcontrollers, one might use DIP switches or jumpers... Last few weeks I am experimenting with another solution - to define parameters on a smartphone GUI and then transfer them into the tiny 8-bit microcontroller using the "flicker" interface. The

## multiplexing code problem

The first problem I see is that you are only turning on the 10s display for 10ms every 1.02s. You might see it flicker, but probably not. You would need to continually refresh both displays in order for vision persistence to make them both appear on solid. Basically you need to add loop inside the for loop containing the two PORTD/PORTB output s

## Noise analysis (flicker noise) of pico Ammeter readings

M given project to do noise analysis of pico ammeter ADC output. here the input is 1pA DC signal. for which i have nearly 100000 output samples. sampling rate is 3.5Kps. these readings have error percentage nearly 0.178%. So i need to do its noise analysis like i have to detect which types of noises it contain? separation of those noises and actual

## Flickering of computer LCD screen

There's this computer installed in a small medical diagnosis center. Since some days the display has begun to flicker when operating under the main supply. However when it operates under a pure sine wave inverter, the flickering dissapears. What can be the probable reason for flickering of LCD screen? Due to some other equipments installed

## Flicker and Thermal Noise Coefficient

Thermal noise for hand calculation is most simply expressed as a drain current noise Idn=4 k T Γ g_ms where g_ms is the source transconductance and Γ a factor smoothly varying from 1/2 in weak inversion to 2/3 in strong inversion. It is valid for all regions of operation. As of flicker that's a much stickier matter since modern models us

## PIC16f877a PWM interface using a bulb with in-build zero crossing optocoupler

For 220Vac you should be using MOC304x not MOC303x What range of control causes flicker? < 10%? Does adding 330R across Triac gate to MT2 help? Triac should not be grounded! That defeats safety isolation. flicker is usually caused by nonlinear lamp load and unequal trigger current in Triac quadrants. Which triac?

## Depletion MOSFET Flicker Noise

Hi all, When operating in saturation, subthreshold, or weak inversion, which MOSFET type has lower flicker noise: enhancement-mode or depletion-mode? Intuitively, the depletion FET should have lower flicker noise because the E-field within the gate oxide pushes carriers away from interfacial traps at the surface. Is there any data or other solid

## ac noise analysis using hspice

I am doing noise analysis of op amp using hspice. The value of inosie, outnoise , flicker noise and thermal noise obtained from analysis is zero. Why??

## Fix a faulty flickering G9 led lamp

I wonder what causes the flicker at low conduction angles. I reason that the flicker is faulty switching on either positive or negative cycles due differences in the triac quadrant characteristics and if the load current gets below the holding current, the triac will turn off. SO what determines the holding current? THe ESR value on the 2.2uF mig

## Flicker noise in FETs

Generally flicker noise tends to rise with Vov, see the following snippet. Hence triode region (large Vov, small Vds) will probably exhibit more flicker noise than saturation region. Still, operation in strong inversion mode (with large Vov and large Vds) would probably exhibit even more flicker noise in saturation region. 102937[

## Running a torch from USB??

Hi guys, I've got a 9 led torch - it takes 3x aaa batteries. So 4.5 volt? I want to get it running from a USB cable. I tried today - I used a USB to mini usb cable - the black and red wires. The torch lit up -- but the LEDs were CRAZY bright - started to flicker, and the touch was getting hotter and hotter. When I tried it again with ba

## help me in finding flicker noise frequency for calculating phase noise for LC VCO

hai, help me in finding flicker noise frequency for calculating phase noise for LC VCO also how to calculate current at particular node using T-spice i tried using probe command it shows as \only_varactor_with_DGFET_20131204_153404.tsim but i did not find the voltage in manual they mentioned as .probe tran Saves all node voltages and vo

## questions on current noise simulation

Because of flicker noise, should low freq noise be higher than high freq noise? Voltage noise yes, current noise no. See a typical MOSFET noise

## Noise of Feedback DAC in CT-DSM ADC

In Continuous Time Delta Sigma ADC, there are two options in Feedback DAC generally. (1) Current DAC (2) Voltage DAC or Resistive DAC Regarding thermal and flicker noise, (2) have advantage. Regarding calibration for multi level DAC, (1) have advantage. Regarding speed, (1) have advantage. (1) occupy large area than (2) generally.

## Flicker noise in poly resistnces

hello, can anyone tell me if there is a direst equation describing the flicker noise (in uV) inside the poly resistances ? thnx

## Internal Oscillator frequency of PIC16f676

Thanx for the rply. I am running PWM on Timer 0 interrupt. But when PWM starts flicker for LOAD on/off increses. What must be the reason. when PWM starts flicker for LOAD on/off increses?? I am sorry I didn't get your words fully. what do you mean by LOAD?? Best regards

## Do n+ / p+ diffusion resistors exhibit flicker noise?

Is it that flicker noise in diffusion resistors is perhaps not that big a component of the overall noise or something? flicker noise emerges from interferences of current flow at any boundary interfaces (worst in MOS channels). Diffusion resistors show more interface area (actually the whole reverse-biased silic

## controlling CFLs with SSRs

I spotted that too. Normal current for a 30W CFL at 220V would be around 140mA so restricting it to 7mA might be enough to stop it working but it might flicker instead. I would be inclined to drop C1 to 0.01uF to increase it's reactance to ~320K and see if it worked. The other alternative is to put a resistive load across the CFL but that wastes

## 0.5V GaAs LNA with 1dB NF??

It will not make sense without knowing the foundry/technology which has been used in the design of this LNA but it may be possible.. But GaAs devices introduce pretty high noises at lower frequencies around 50-200MHz because of flicker effect.If they overcome this problem, please let us know..;-)