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  1. Replies
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    Closed: Re: Bridge Rectifier won't Rectify

    Compensation ideally works only for a fixed frequency. Why the frequencies seen in post 14 for the square pulses are so low?
  2. Closed: Re: Pulse transformer output measured vs. calculated?

    No, I do not wish to know the internal details. I just want to know if you substitute a resistor instead of the pulse transformer, what kind of waveform you will get? say you use a 1k or 10k resistor...
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    Closed: Re: Bridge Rectifier won't Rectify

    For low frequency (say 50-60Hz), you can protect the diodes with capacitors and resistors. They help suppress spikes.

    The capacitor cannot be used for high frequency. I do not know other ways to...
  4. Closed: Re: Toroids EMI suppression choce choice of core material ?

    As an inductor you can use either one. Obviously the smaller one is cheaper and equally effective.

    But you do not mention the power to be handled.

    Yes, a lot of power is going to come back to...
  5. Closed: Re: Pulse transformer output measured vs. calculated?

    Once you use a voltage divider, your bandwidth is also getting scaled down in the same ratio, right? Similar to gain-bandwidth product

    Plus, frequency compensation should be done with this divider...
  6. Closed: Re: Pulse transformer output measured vs. calculated?

    I am not quite sure. How are you generating the pulse?

    The waveform seen is typical ringing process (it hit a bell and it produces sound that slowly dies in intensity).

    I still suspect that the...
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    Closed: Re: Bridge Rectifier won't Rectify

    The first peak is around 8 kv; the current should be around 270mA. The diodes are not rectifying.

    In the previous graph, with a load of 100Mohm, you get currents of the order of microamps. Small...
  8. Closed: Re: Pulse transformer output measured vs. calculated?

    In response to a voltage pulse, the current increases linearly; that is clearly seen in the graph.

    In both the plots, I see considerable high frequency ringing. Both voltage and current plots show...
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    Closed: Re: Bridge Rectifier won't Rectify

    I suspect that the voltage is not getting shared equally by the diodes. You need to put resistors in parallel with the diodes so that the applied voltage is divided equally.

    The value of the...
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    Closed: Re: dc motor theory question??? Maths

    I really do not know where to start.

    But you have calculated somehow; tell us the steps.

    Once we know the steps we can comment.

    How to convert the motor torque 40nm to watts?

    Is it a DC...
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    [SOLVED]Closed: Re: magnet wire parasitic properties

    Ferrites are soft or hard depends on their magnetic properties. Yes, they are not "soft" materials, because you will take lots of time to cut one.

    Just like soft iron does not store magnetism, it...
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    Closed: Re: Subtract two dc voltages.

    I am confused: how it is going to work in real life?

    You are connecting to batteries in series but measuring the voltage across the 9V battery.

    Am I missing something?
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    Closed: Re: Single conductor inside hollow conductor

    I do not have any direct explanation but these come to the mind:

    1. The two conductors are not symmetrically places. Because the shield is floating, a large part of the electric field is blocked...
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    Closed: Re: Help with medication timer design

    Me too!

    But my medicines do not come in bottles; they come in Al foil strips. And I need to take them at different times. All but one are to be taken once a day but I forget one or the other quite...
  15. Closed: Re: 1 minute vs 1 second isolation voltage test for isolated offline SMPS transform

    You forgot to mention the frequency.

    This is basically a test for the dielectric. Some certification agencies require the isolation test.

    The voltage must be ramped slowly (else your test will...
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    Closed: Re: Single conductor inside hollow conductor

    Potential is related to an electric field. There is nothing about "static" charge distribution: of course if the charges are moving, you get an electromagnetic radiation.

    Electromagnetic...
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    Closed: Re: Whats the best way to ESD damage a PCB

    Most of the components are sensitive (to ESD) before they are put in place. Once they are in the board, they are interconnected and are far more resistant to ESD.

    Running up and down the stairs...
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    Closed: Re: Waste pulse energy recovery

    340 kW in 140 uS corresponds to about 47.6J per pulse. Because you are handling large currents and high voltages, this may (or may not) be much.

    To reduce the ringing effect:

    Take either the...
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    Closed: Re: Waste pulse energy recovery

    If you have learnt that negative power is dissipated, you are wrong.

    If the voltage and current has opposite signs, the instantaneous resistance is also negative.

    In this particular case, you...
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    [SOLVED]Closed: Re: 12 vdc led running very hot

    Sure; Cut off 2-3 cm length and tightly coil around the resistor and fix with some glue.

    But you are worried unnecessarily. Whereas it is a very good habit to ensure that every component works...
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    [SOLVED]Closed: Re: 12 vdc led running very hot

    Of course. The higher the resistance value, the lower is the dissipation (at const voltage).

    The small 5mm LEDs can take max 20mA (at least for the garden variety). With a 12V supply (most of it...
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    Closed: Re: Soldering on Battery Terminals

    Simple questions do not have simple answers.

    Most common cells (except the very old C and D type ZnCl2 cells) have contacts that are Ni plated. They are easier to solder and still easier to weld....
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    Closed: Re: Waste pulse energy recovery

    I do not see that so clearly.

    This is a typical waveform for a damped harmonic motion with two time constants.The two time constants are not even close and we can study them independently.

    In...
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    Closed: Re: Waste pulse energy recovery

    Using absolute values to calculate power is not correct.

    Your case appears to have considerable source reactance. Hence any correction need to be made to the source side.

    Power factor...
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    Closed: Re: Waste pulse energy recovery

    More clarity needed.

    Voltage and current do not appear to be in phase.

    You can multiply current and voltage point by point and plot on the same graph.

    The applied pulse is not clearly seen....
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