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Type: Posts; User: betwixt

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    Closed: Re: cd4060 used in sensor circuit

    No idea.
    But I can tell you that you can't measure TDS with an electrical probe. It has to be done optically and I don't see any source or detector on that board or cable.

    Brian.
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    Closed: Re: LTC 4367 Transistor burning Issues

    Apologies, your original schematic shows an unconnected source at pin 9 but I see from the data sheet it is an 8-pin device with internally connected source pins.

    Brian.
  3. Closed: Re: SMPS Switch off and switch on repeatedly

    Your finger falls off?

    Seriously, there must be 10,000 different designs of SMPS doing 10,000 different tasks, how do you expect us to answer a question like that.

    Brian.
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    Closed: Re: PIR sensor project

    The actual sensor device in a PIR module normally has two different sensors side-by-side inside it, so that they do not detect background IR, which is always present, the output is the difference...
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    Closed: Re: PIR sensor project

    I don't know of any such device but most PIR sensors are mounted in 'zoned' lenses anyway. They work by comparing the IR in adjacent zones (A B A B A B A B...) so if you move them the distinction...
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    Closed: Re: carbon arc modalities

    I have no experience of this but I would guess it would be difficult to establish an arc with a power limited source. If my thinking is right, it takes more power to take the arc temperature to...
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    Closed: Re: LTC 4367 Transistor burning Issues

    I presume the source connection on Q2 is connected to +50V, it isn't shown in the schematic.
    Gradual reduction in output suggests something is overheating. You are running the device at it's maximum...
  8. Closed: Re: Will I be able to drive LED with attached analog circuit ?

    It will work but I would use a bipolar transistor in this circuit. My reasoning is that to use the MOSFET as a switch its gate voltage needs raising more than knee voltage above the source pin. In a...
  9. Closed: Re: 4x4 Keypad for Arduino with color keys and braille texture (no membrane buttons)

    Making your own keypad is fairly easy and you can buy Braille keypad stickers from Amazon and others. You could consider these:...
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    Closed: Re: Halogen Lamp Limit Resistor?

    Look at this link: https://www.electroschematics.com/9730/high-power-led-dimmer/

    It is for high power LEDs but it will work just as well with a Halogen lamp. Note that it runs on DC, you have not...
  11. Closed: Re: Sine PWM calculated with pic, instead of using table

    That seems a far better solution. There is an error in your table at 199 but that may be because of text formatting on Edaboard, I see a gap between 19 and 9.

    Personally, I would also set the PWM...
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    Closed: Re: Bridge Rectifier won't Rectify

    The scope traces look suspicious to me. Given that the scope, probe and stray capacitance is effectively the load after 100M of resistance, I would have expected the opposite to have happened, the...
  13. Closed: Re: Sine PWM calculated with pic, instead of using table

    Remember that you can't produce two different PWM signals simultaneously with only one PWM generator but if one of the signals is the inverse of the other you can use a logic inverter to produce it....
  14. Closed: Re: Sine PWM calculated with pic, instead of using table

    I think it will work but the waveform will be quite distorted. I do not use BASIC at all but I would guess the PULSOUT command uses a software loop to create the delay. It is unlikely the delay will...
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    Closed: Re: Active HF phase shifter?

    The phase shift in your original post depends on the reactance of the capacitor so it varies with frequency. If you manage to find suitable values it will still need 'tuning' to each frequency to...
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    Closed: Re: Bridge Rectifier won't Rectify

    Are you compensating the probe alone or with the HV divider resistors attached? You need to apply the square wave through the divider then do the compensation. I suspect you have inadvertently added...
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    Closed: Re: Bridge Rectifier won't Rectify

    What exactly is driving them, the waveform suggests it is a single pulse and the transformer is 'ringing'.
    Are the tabs mounted on a a heatsink? I appreciate they are insulated but the accumulated...
  18. Closed: Re: NodeMCU sinking current through DIO while power is off

    The voltage ratings and polarity limitations are from the DIO pins (and others) to the ground pin. Ask yourself what voltage will there be between DIO pins and ground if you connect the negative side...
  19. Closed: Re: NodeMCU sinking current through DIO while power is off

    I'm hardly surprised, disconnecting the ground will almost certainly violate the maximum voltage and polarity ratings of the nodeMCU.
    Consider that the DIO pin effectively becomes the ground...
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    Closed: Re: damaged remote control

    Cleaning the board AND the keypad mat is needed. I doubt the electronics is damaged.
    Take the floppy plastic keypad mat and wash it in warm (not hot) water with detergent, then rinse it and leave it...
  21. Closed: Re: Problem with Logitech Audio PCB (No Sound Output)

    It might but it won't work as well and you risk it being damaged or even exploding. You can generally increase the value and working voltages but you should never reduce them.
    If that part was...
  22. Closed: Re: Why does my homemade Yagi wifi antenna perform so poorly?

    Where is the folded dipole?
    The ends of the feeder cable need tidying up (they are part of the dipole) but they should go to the ends of the folded loop.
    Folding the dipole reduces its impedance...
  23. Closed: Re: interfacing IR remote using NEC protocol - mikroc for PIC

    Wow! That's a fast PIC!

    I think hexreader was referring to the PIC clock frequency not your PC.

    Brian.
  24. Closed: Re: circuit design help analog to Potentiometer

    From the schematic it looks like you don't need a potentiometer at all, just a variable voltage.

    The "CVS MAX TRIM" and "CVI MIN TRIM" circuits just set the voltages at the ends of R1 to restrict...
  25. Closed: Re: Problem with Logitech Audio PCB (No Sound Output)

    The top picture looks correct to me, assuming the number refer to the actual pin numbers on the IC.
    Be aware that reversing the IC will probably kill it, even if it doesn't get hot.

    However, just...
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