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  1. AnalogKid

    help connecting 555 timer

    How rapidly are you scanning the sensors? Your pseudo-radar approach will work in theory, but not in practice. A timing resolution of 1/10th of 1/2688th of whatever the scanning interval is (at least 26.88 seconds) is not possible with R-C timers. It's not the length of the interval, it's the...
  2. AnalogKid

    help connecting 555 timer

    Only to you. Is there to be a 0.01 second gap between each of the successive outputs, between the input trigger pulse and only the first output, or what?? What are the output pulse widths of each of the other 99 555s? If alike, do they have to be *exactly* alike? That will be nearly...
  3. AnalogKid

    can't figure what the hell is wrong !

    Your idea of "typical NPN switching" is actually a narrow case of a much wider range of circuits. Pulling the base of PNP (not NPN) transistor up to 5 V will turn it off only if the emitter is connected to 5 V. Typical for many logic circuits, not for medical, industrial control, etc...
  4. AnalogKid

    can't figure what the hell is wrong !

    In the first schematic in post #1, where does the trace on IC2 pin 9 go? If it goes to GND, that turns on all outputs all the time forever and ever until the end of eternity. ak
  5. AnalogKid

    Sound Sensor

    The circuit is fairly simple. but unless you use a pre-calibrated, laboratory-grade microphone capsule (expensive), you will need a way to calibrate the circuit. Do you have the capability for that? ak
  6. AnalogKid

    Schematic capture software recommendation

    For the next few weeks I will be without my beloved ViewDRAW. I'm looking for experience-based recommendations for a schematic drafting package. Requirements: 1. Local operation. No cloud-based libraries, website GUI, etc. Download and install; Cut internet cable; Use. 2. Prepackaged...
  7. AnalogKid

    Attenuating a voltage signal

    And the manufacturer and model number of the Hall sensor. Some are voltage output, some are current output, etc. ak
  8. AnalogKid

    Amplifying current in a sine wave

    Since I already asked what the frequency range is, is there a reason you won't tell us? So, you want a small amplifier circuit that can produce a peak current of 0.37 A at an output voltage of 5.0 V. The amplifier circuit has unity gain because the input signal varies between 0 V and +5 V...
  9. AnalogKid

    Amplifying current in a sine wave

    Can you post a datasheet for the valve, since your question is not clear? What frequency or frequency range? Is the AC waveform symmetrical about ground? What is EVP? ak
  10. AnalogKid

    Attenuating a voltage signal

    Not sure what "positive AC" means, since AC usually means alternating (the "A" in AC) between positive and negative current, and hence, positive and negative voltages. Also, 17 volts what? RMS, peak, peak-to-peak, average...? ak
  11. AnalogKid

    help to calculate frequency of CD40106BC schmitt trigger square oscillator

    1. From post #1, 3.9 V and 5.9 V are not symmetrical about Vdd/2. 3.9 V and 6.1 V are, for a delta-V of 2.2 V, much closer to your original information. 2. Internally, the transition voltages hve both a fixed and a ratiometric component. This is why their overall percentages shift as Vdd...
  12. AnalogKid

    12v to 5v

    Yes, always; no exceptions, ever. ak
  13. AnalogKid

    Piezo sensor circuit

    Not the easiest sensor in the world to interface to. A typical interface circuit would be a nice starting point, but the data sheet doesn't have one. Other than that, not at all difficult. What is the current through the LED string, and lit up for how long? ak
  14. AnalogKid

    Auto reversing polarity after a few milliseconds (for solenoid control)

    1. Any idea what the steady state current through the solenoid coil is? 2. There is nothing in the valve description that mentions having to reverse the current through the coil. Are you sure this is necessary? ak
  15. AnalogKid

    Need help with muscle stimulator project

    Patient-contact electronics are *v*e*r*y* dangerous. What output voltage are you trying to produce, and why? What research have you done into TENS waveforms, pad resistance, skin resistance, and ***current limiting***? Also, what is the value of the inductor in the first schematic, and...
  16. AnalogKid

    Locking cat door, really need some help...

    Posts 10, 13, 14. ak
  17. AnalogKid

    Advice needed

    For the 15 full years between 1998 and 2015, do you have the annual totals for number of children baked alive (your words)? ak
  18. AnalogKid

    Audio amplifier to amplify a load cell signal

    The instrumentation amplifier you have now probably can act as a low pass filter to remove some of the noise, with a few additional components. ak
  19. AnalogKid

    Remote controlled starting grid lights circuit help

    Nope. The outputs of the 2804 go LOW when active. Did any documentation come with the board?
  20. AnalogKid

    replacing 4.7k pots with 5k on negative feedback op-amp circuit

    Without a schematic, it's *impossible* to say. But almost certainly all of the pots do not do the same thing, so changing the value might affect some circuits more than others. ak
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