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Type: Posts; User: betwixt

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  1. Replies
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    Closed: Re: Looking for a single SMD pin header

    Why not simply use copper pads?

    Brian.
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    [PIC]Closed: Re: Code for dspic33fj32mc204

    You didn't look very far. There is a register in that device specifically for setting PWM deadtime. Look at page 170.

    Brian.
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    Closed: Re: Specifications beyond data sheet...

    No guarantees of course but I would guess it would work over quite a wide range. The lower limit is usually decided by internal gain dropping due to capacitors in the silicon, the upper frequency by...
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    Closed: Re: CRT Hitachi turns off

    I've traced the schematic. My first guess is C756 is faulty.
    Do you have a voltmeter if I ask you to take measurements?

    Brian.
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    Closed: Re: CRT Hitachi turns off

    Those a 'flyback lines', it's the dots that normally make the picture as they scan back to the top of the screen ready for the next visible raster. They are spaced out because the sweep back to the...
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    Closed: Re: CRT Hitachi turns off

    Can you post a picture of the horizontal lines or at least describe them please.
    Are they overlayed on a normal picture or are they against a bright background?

    Brian.
  7. Closed: Re: Need to ensure SMPS output filter has at least 10mR of ESR...use "ESR resistor"?

    One milliOhm is incredibly small, the chances are the ESR of the capacitors is higher than that already and the added resistance of the connection to it will make up any difference anyway. I don't...
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    Re: learning to detect radio signal.

    A spectrum analyzer would be a far better instrument for measuring at those frequencies!

    Brian.
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    Re: learning to detect radio signal.

    You stand absolutely zero chance of a multimeter reading that!

    Consider that when using frequencies in that range you need at the very least coaxial cables and more likely matched strip lines...
  10. Closed: Re: Questions of mechanical to electrical energy transfer

    Follow Brad's advice but please bear in mind that nobody makes a 'dynamo' charger specifically for the voltage and current you need. I cases like this you generally have to add some electronics to...
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    Re: learning to detect radio signal.

    Yes, an ordinary meter will measure voltage up to its maximum frequency. Typically for DVMs that will be a few KHz.

    You can rectify the signal and measure the resulting DC, this is how "field...
  12. Closed: Re: Rectifier diodes with bypass capīs & gounding speaker basketīs

    That is just a normal toroidal transformer with primary and secondary on different bobbins. That construction is normally used when very high voltage isolation is needed between primary and secondary...
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    Closed: Re: Repeat Cycle using timer application

    I'm still confused about what this code is supposed to do and in particular how it produces the display. Am I correct in thinking the lines:

    #define DISPCLK RB5
    #define DISPDATA ...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    Looking at data sheets and application notes, the snubber capacitor values range from 3.3nF up to 10nF, 103pF still seems unreasonably low to have any significant effect.

    I see some designs using...
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    Closed: Re: uc3842/3843 Vcc problem in smps.

    If the schematic is to be trusted, shouldn't C1/R2 be across the rectifier?
    Is D5 doing anything?
    103pF in the snubber circuit seems far too small, should it be 1nF?
    All other points made by...
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    Closed: Re: Repeat Cycle using timer application

    I explained the timing issues to nayakajit87 and how to structure the ISR efficiently in a previous post but it has been ignored.

    As well as that, I can't see where 'LED_MS_Flag" gets reset...
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    Closed: Re: soldering with silver content

    Most electrical solder contains some silver but higher concentrations are used when soldering some surface mount components with silver doped end connections. It helps to limit the migration of metal...
  18. Closed: Re: Please help power supply dead 110V to 24vdc 5vdc

    The big capacitor is fed directly from the bridge rectifier which in turn is fed through the filter and fuse from the AC input. It could be the NTC if that's what is hidden under the white silicone...
  19. Closed: Re: Please help power supply dead 110V to 24vdc 5vdc

    Two points to make here:

    1. You show DC voltages across the transformer primary and secondary, you can't measure these voltages with a normal test meter and they are not DC anyway.

    2. There...
  20. Closed: Re: Rectifier diodes with bypass capīs & gounding speaker basketīs

    What is an "R-Core" transformer?

    We need to backtrack here - regardless of the advice that you don't need them, are you proposing snubbers across the AC connection from the transformer or across...
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    Closed: Re: Overvoltage Protection

    Provided you use the specified transistor it should be fine, its internal base resistor will limit the current to a safe level.

    Brian.
  22. Closed: Re: Displaying the time parameter using Timer interrupt

    Additionally, please do what I suggested in the ISR. Reduce it to:

    void interrupt isr(void)
    {
    if (TMR1IF)
    {
    TMR1IF = 0;
    TMR1H = 0xFE;
    TMR1L = 0x0C;// timer interrupt for 1ms...
  23. Closed: Re: Displaying the time parameter using Timer interrupt

    I couldn't read code so badly formatted and commented. Please stick to one style to make it easier to read.
    I think I managed to unscramble it as:


    void interrupt isr(void)
    {
    ...
  24. Closed: Re: 7 segment LED with integrated zener diode .

    LEDs are already constant voltage devices so there is no point in placing a Zener across them. If reverse voltage may be an issue, a normal diode will work just as well. As Klaus stated, the problem...
  25. Closed: Re: Where to buy Electronics components in UK for domestic use?

    Try Rapid Electronics https://www.rapidonline.com/ they carry vast stocks of components and construction materials and for small deliveries they use Royal Mail.

    Select 'industry' when you get to...
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