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    Reverse Photoresistor for volume control when nearing

    Arduino and a distance sensor, use PWM in Arduino as a control voltage on a JFET voltage divider, or a I2C variable resistor in a divider..... https://randomnerdtutorials.com/complete-guide-for-ultrasonic-sensor-hc-sr04/ I2C resistor, app circuits on datasheet ...
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    Sallen Key Low Pass Filter, bandpass filter

    Bunch of videos here : https://tools.analog.com/en/filterwizard/ Regards, Dana.
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    Not sure what sensor to use

    https://www.kemet.com/en/us/sensors/environmental-sensors/motion-detection.html Regards, Dana.
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    Sallen Key Low Pass Filter, bandpass filter

    What is your architecture right now of choice ? if you have 16 bands you need 16 filters, and with 20 leds / band thats 2 LM3914 / band or 32 LM3914. So 48 parts so far, and a ton of passives. You sure this is the way you want to go ? Versus one part doing a FFT with 16 bins, (thats software...
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    7486 IC problem

    Are you trying to drive motor directly with 7486 output ? You cannot do that, it does not have enough power / current capability to do that. Plus you may have ruined the 7486 with the inductive load transients that a motor produces. Regards, Dana.
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    Spectrum analyser Equalizer project how to go about it?

    PSOC 4 64 point FFT done in < 700 uS, and thats a low end part. I believe this was not done with the single cycle 32 bit multiplier that is also on the chip. Eg. could have been much faster. 64 point FFT yields 32 frequencies. SAR being used can produce up to 138K SPS, although the 700 us was...
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    Lowering 54vdc to 48-50vdc

    No a divider would not work. As soon as amp turns on and pulls 8A the divider output would collapse if you had designed it for outout V of 54 with no load. Slightly better way is just a series R, it has to handle 54 - 48 V, a drop of 6 volts, and 8 A thru it, so R = 6 / 8 = .75 ohms. Its power...
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    Lowering 54vdc to 48-50vdc

    I dont think you can buy charge pump converters at this W / V / I ratings ? But then I saw this and learned - https://www.analog.com/en/parametricsearch/11458#/p5349=10|25 But ratings needed = $ 10+ kinds of cost..... You can do this with a linear solution which results in a lot of...
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    Electronics Engineers Questions

    Age ~ 10, was fascinated with radios and TVs, I was tearing them apart, saving the components. Soon started using them in simple things like one transistor radio, light activated relay...... My first job as EE a production engineer on a PMOS line. Became interested in applying what is now "big...
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    Electronics Engeeniring

    And the rest of us should improve our Chinese and Indian language skills. Regards, Dana.
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    Time to Digital Converter

    1) A digital delay (counter) needs a clock and some timing function to sync. It has / adds jitter to the timing event. Commonly used to wait for data to settle at some input, like a flip flop, before attempting to clock it in. Its the whole issue of metastability -...
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    Triac problem

    This might be helpful - http://www.bitsavers.org/components/ge/1972_GE_SCR_Manual_5ed.pdf Regards, Dana.
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    Spectrum analyser Equalizer project how to go about it?

    1) You turn off all leds by writing 0 to all transistor base inputs. Then all column enables are off. 2) Then you write what leds you want on, and off, to the digital outputs. 3) Then you enable the whole column to turn on the leds that were requested to be on in step 2) by writing a 1 to...
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    Spectrum analyser Equalizer project how to go about it?

    And here we have a web based one : Regards, Dana.
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    Spectrum analyser Equalizer project how to go about it?

    In the example post #204 its column centric, that is you enable the entire column, 'and then turn on the outputs of the row leds you want to light up in that column. Then move on to the next column. All so fast that human eye thinks its all on at samer time. Note human eye has persistence, that...
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    Spectrum analyser Equalizer project how to go about it?

    If your processor has enough I/O drive directly from processor. An example : You basically do one column at a time in code, enable the column drive transistor and output the the data to turn on the desired led(s) in that column. In the case of using FFT that data is formatted from the...
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    Sallen Key Low Pass Filter, bandpass filter

  18. D

    Sallen Key Low Pass Filter, bandpass filter

    Signal chain, mic >> filter >> LM3914 is the signal chain
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    Sallen Key Low Pass Filter, bandpass filter

    G - gain. Yes trial and error with the following caveats : One can start at either end of the chain, and modify elements in chain to suit. One overriding considerations is when considering noise taking the most G at first element in chain is prudent for S/N, signal/ noise considerations...
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    Sallen Key Low Pass Filter, bandpass filter

    This question has led, over the years, to thousands of ap notes and books on that very subject. Ideally one wants a single frequency (many applications) to pass thru a BPF type filter and all other freq content suppressed. Thats the classic "brick wall filter" so often pursued. But thats...
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