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  1. Replies
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    Closed: Re: I cannot power that pelletier module

    It's generally no good idea to operate a peltier element with fixed voltage supply because for each combination of heat sink thermal resistance, ambient temperature and pumped power there's an...
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    Closed: Re: Generating a frequncy

    555 datasheet has application circuits and formulas for pulse width and frequency calculation.

    As for the 27 MHz generation, I was expecting a frequency stable sine oscillator (e.g. crystal based)...
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    Closed: Re: I cannot power that pelletier module

    Do you have a full datasheet with I/V/ΔT curves? What's the expected hot side temperature for -30° cold side? Did you check the actual temperature?

    Most likely problem is insufficient heat...
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    Closed: Re: Generating a frequncy

    Have a 555 circuit generating the modulation waveform and a 27 MHz crystal oscillator enabled by the pulse signal. 8 cm is rather short for 11m wavelength, don't expect large antenna efficiency.
  5. [SOLVED]Closed: Re: LM741 Amplifier not working with IR2110 IC [PROTUES]

    The design fault is to connect VDD to 12V, with 5V supply, the IR2110 logic inputs can be driven by processor signals directly.
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    Closed: Re: Stable PWM during Voltage Loss

    This sounds rather confused. Buffering the controller supply for 50 ms shouldn't be a problem, how 5 A and 50 mF come into play?
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    Closed: Re: Problem with my echo circuit using PT2399

    The standard PT2399 application circuit is sending the low-pass filtered original signal to the output, that's not appropriate for an echo effect connected to the effect send and return of a mixing...
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    Closed: Re: what's the rf cavity filter tuning principle

    Your colored hand sketched annotation of the drawing makes no sense, particularly the blue circle around a coupling slit. There's no tuning bolt in this position.

    Why don't you provide a readable...
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    Closed: Re: Hand soldering a 6x6mm QFN (28pin)

    Don't necessarily need stencil, applying solder paste with a syringe is possible as well. Reflow by hot plate or hot air.
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    Closed: Re: Differential probe build

    Source = the voltage you are probing
  11. Closed: Re: What is this sensor? (Can detect the clap sound)

    It looks quite similar to an ultrasonic piezo transducer. I doubt that it has much sensitivity in the audible sound range. Measuring the resonance frequency would be a first step to learn about its...
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    Closed: Re: Differential probe build

    10 pF input capacitance is still large for an active 100 MHz probe but at least acceptable for a number of measurement problems. To realize the bandwidth, the source impedance must be lower than 150...
  13. Closed: Re: Questions about a circuit interfacing a DC fan via open drain way

    According to fan datasheet, the PWM input can be driven by 5V logic directly. No need for additional transistors.
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    Closed: Re: Does Solid State Marx Generators actually work?

    Sure, if parasitic capacitance causes the voltage drop, it must have a similar value. But is the capacitance value realistic?

    Capacitance can be measured with LCR meter or various homemade...
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    Closed: Re: Does Solid State Marx Generators actually work?

    Parasitic capacitances surely matter, surprising that you start now to think about it. 2 x 2nF however isn't but a shot in the dark and should be justified with datasheet specs and measurements. Are...
  16. Closed: Re: Power Supply for M95 GSM module to be compatible with ATEX limitations.

    I don't see that any of the V, I or P limits can be achieved other than with active electronic circuits. There are some issues like avoiding additional L and C elements in the IS circuit that may...
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    Closed: Re: what's the rf cavity filter tuning principle

    The tuning method can be basically described as variable capacitance. To understand the whole filter design, including the tuning options, you should read more about cavity filters.
  18. Closed: Re: Choice of capacitors for DC blocking and 3A AC?

    Choosing the capacitor for exact series resonance is of course possible, but we have to consider the complete circuit. At the end of the day, the capacitor ESL is probably a small fraction of the...
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    Closed: Re: Power amplifier impedance matching

    You can with multiple transmission line stubs. Obviously not all exactly quarter wave length. Smith chart tools like SimSmith will help you to design the matching network.

    As a simple approach...
  20. Closed: Re: Choice of capacitors for DC blocking and 3A AC?

    With effectively no voltage across the capacitor, X7R should be o.k. Major manufacturers have individual datasheets for capacitors, see e.g. Murata 100nF/250V/1206

    154443 154444
  21. Closed: Re: LM3940 (3.3V reg) cannot supply 9V buck-boosk ?

    Next step is to make informative measurements, e.g. oscilloscope waveforms.
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    [51]Closed: Re: SRAM WR pin is not anabled

    I would assume that the code is executed out of the flash memory rather moved to RAM. In this case, the RAM #WR signal won't be pulled low before a write access to XRAM memory happens in the code.
    ...
  23. Closed: Re: can triacs rapidly switch AC into a transformer

    Gate driver should be of course referenced to common source node.

    There are several reasons why the "chopper" circuit can't be used in the shown basic configuration:

    - Mains input filter...
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    [SOLVED]Closed: Re: Sleep mode - dspic33ch128mp508

    Perhaps we can paraphrase the question:

    Is it reasonable to start system level microcontroller programming without studying the datasheet thoroughly and understanding the specific CPU functions?
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    Closed: Re: Hints for pin assignment

    I believe the question has been already answered by Akanimo. All externally connected IO pins, user clock, reset etc. must be present in the top module interface. But not dedicated pins, e.g. power...
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