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Type: Posts; User: betwixt

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  1. Replies
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    Closed: Re: cooler master silent prp 500w pc psu

    There is a "prp 500W" which is a power inverter and there is a "pro 500w" which is a modular PC power supply. I'm guessing from the title this should be "pro" not "prp".

    My first step on all...
  2. [PIC]Closed: Re: Question About Crc8 Picbasic Implementation

    I'm not sure I understand the question.

    The algorithm is the same regardless of the format the digits are presented. I think this is written in Oshonsoft BASIC so the only reference with a '$'...
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    Closed: Re: E-mails about thread replies

    The HTML to PHP interface says everything after the '?' is passed to the interpreter and the '&' delimits individual parameters. There is nothing that makes any specific word do anything.

    However,...
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    Closed: Re: water tornado device

    I looked at the link, it very clearly shows a white 'strirrer' in the bottom of the flask and it even 'explodes' the base contents where you can see the motor.

    So yes, you do need to place the...
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    Closed: Re: Mini SCART TV, does it exist?

    A far better alternative would be to buy a Raspberry Pi, the cost is almost the same and you get a more modern HDMI connection for A/V as well as composite and audio, an Ethernet port, USB for...
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    Closed: Re: Yes-Circuit: Misunderstood or malfunction

    Be careful, transistors can be damaged by swapping their connections over and they will only work when wired correctly.

    What Audioguru said is quite right, did these transistors come pre-wired on...
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    Closed: Re: Yes-Circuit: Misunderstood or malfunction

    Your language skills are perfect!

    From what I can see, you have built it correctly and the values look good.

    If pressing the button makes the LED light up it means T1 is working. What should...
  8. Closed: Re: Use physical button to trigger an IR sensor

    I think we need to see how it connects to your circuit. The answer to your problem depends on whether the sensor side is connected so it lifts the output signal high or whether it pulls it low. It...
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    Closed: Re: water tornado device

    A small disk with a fin or a small propeller sit in the bottom of the glass. In the base there is a small motor spinning a magnet around. The rotating magnetic field drags the disk around and stirs...
  10. Closed: Re: Circuit don't work in Microcap (555-based class-D)

    Don't expect particularly good results from that circuit. In astable mode the control pin can change the frequency as much as the pulse width and the output is not AC coupled so it shouldn't be used...
  11. Closed: Re: Questions about the components in a circuit (metal piece)

    Most likely a negative ion source.

    Some 'purifiers' generate small levels of ozone, claiming it makes the air purer although more likely it produces a slight scent to make people think it does...
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    Closed: Re: Random Time Delay in C

    Wouldn't this do the same thing:
    delay(((rand() % 6) * 1000);

    Brian.
  13. [SOLVED]Closed: Re: PIC24FJ256GB210 Controlling Output Voltage

    The resistor and LED seem OK but what is the supply voltage (VDD) to the PIC. It needs to be a little higher than the LED needs to allow for some drop in the internal circuits. The maximum...
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    Closed: Re: What does 1

    Are you sure?
    1 << (twint) shifts a '1' left by '(twint)' times, it creates a value but does it change the contents of a register?

    Brian.
  15. Closed: Re: Measuring voltage drop across a diode in a switching circuit

    So if you did this: (forgive the crude graphics)
    +8V ------ Diode ------- (no connection)
    0V ----------------------------------------
    And you place a meter across the diode you would expect to see...
  16. Closed: Re: Measuring voltage drop across a diode in a switching circuit

    Only when the diode is conducting and passing enough current. If the voltage can't drop below 7.7V after the diodes it probably means there is already that much from storage in the capacitors or...
  17. Closed: Re: Variable Resistor clamping and output behaviour for LM2596-ADJ

    I've never seen a regulator that takes it's feedback from the input voltage!
    I suspect R36 should go to ground instead of the input.

    To get the voltages you need, find the values for the lowest...
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    Closed: Re: Will a filter block this waveform?

    I think the bottom line is this:

    If you want a clean 40MHz signal it is best to generate one as near a sine wave as possible then use minimal filtering to eliminate harmonics. If you want to start...
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    Closed: Re: HUM in transmitter PSU

    That suggests you are becoming part of the signal path.
    Can you check that the PSU you are using really has a ground connection. There should be one but I'm thinking if you are using a laptop supply...
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    Closed: Re: HUM in transmitter PSU

    Only that there is no frequency modulation on the carrier. When receiving in CW mode you probably wouldn't hear very low frequencies because of the receiver audio filtering.

    What happens if you...
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    Closed: Re: pull pull down meaningon GPIO

    You are not noticing the resistor symbols on the diagram.

    The pull-up and pull-down are not direct connections to VDD or VSS, they enable a weak current source to maintain the pin in a known state...
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    Closed: Re: Will a filter block this waveform?

    Not necessarily, but probably.
    If the module produced a pure sine wave output it would not have any harmonics. A sine wave is a single frequency. If the output is not a sine wave, even with the...
  23. Closed: Re: RFID Transponder transmission and reception working

    A bit over simplified but this will give you the general idea:

    In RFID systems, the transmitter sends pulses at the chosen frequency, it also monitors the amplitude of pulses it sends.
    The 'tag'...
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    Closed: Re: Will a filter block this waveform?

    Does not compute Will Robinson. (with apologies to 'Lost in space' fans). A crystal oscillator generally can't be used for FM transmission.

    I'm guessing you used a crystal oscillator module,...
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    Closed: Re: question regarding this C operations

    It is a pointer, usually to a structure member.

    Brian.
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