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  1. AnalogKid

    Help with basic counter circuit

    Read the entire page, including this paragraph: 2-digit BCD Counter from 00 to 99 ak
  2. AnalogKid

    Electric Guitar Ampenstein

    Let's start with some actual information, like the company name, product name, and model number for each amp, plus close-up photos of the front and rear panels. Or, even better, schematics. ak
  3. AnalogKid

    Race Car Headlight Flasher

    Post #1 is pretty clear about using the headlights already on the car. Here is a first-pass at a single-chip solution. If this seems overly complex, it's because there are a few other things going on - input power transient protection, input power noise filter, input power-on LED, output...
  4. AnalogKid

    Race Car Headlight Flasher

    "We don't have to get the crew off the sub. He would have had to do that. We just have to figure out what he's going to do." - John Patrick Ryan, "The Hunt For Red October" (1990) The car already has headlight power switching designed and qualified for those lights in that car. Rather than...
  5. AnalogKid

    Race Car Headlight Flasher

    An old statistic is that 40% ov the lawyers in the *world* are in the US. A chunk of that large price is liability insurance. If you narrow the universe of possibilities that a programmable circuit allows down to a specific set of actions, then this can be done with random logic devices, and...
  6. AnalogKid

    Rain sensor alarm

    The board above the box and the board wired into the box are not the same. The odds are that the beeper has an oscillator circuit built in, but it might be driven by an oscillator on board. Any way to sketch an approximate schematic, or provide higher resolution images of both sides? ak
  7. AnalogKid

    Rain sensor alarm

    Yes. Put the sensor on the outside of a waterproof plastic enclosure, with the sensor electronics, wireless transmitter, and battery inside. Make sure to seal the hole where the wires go outside to the sensor. Note that you will have to change the battery every few days or weeks, depending on...
  8. AnalogKid

    Piezo To Detect Sound

    That is the basic signal path to start. You probably will wind up adding filters or a rate limiter. ak
  9. AnalogKid

    Piezo To Detect Sound

    Also recommend an electret mic cartridge over a piezo disc. And - if you talk with the people who make glass break detectors for home and commercial security systems, you lean stuff. For example, there is a large, very-low-frequency component to the sound of glass breaking, and that is the...
  10. AnalogKid

    555 IC not amplifying enough

    First, the component values in post #1 are off by about 100-to-1. I'm surprised the chip does anything. Read the datasheet. Second, you have not mentioned a speaker anywhere. Without one, a 555 circuit will not shatter glass because glass is not a conductor. With one, a 555 circuit will not...
  11. AnalogKid

    voltage and current relationship for capacitor?

    If the capacitor is connected across a DC power supply and the supply doesn't suck, then it's output voltage is not changing, so neither the voltage across the capacitor nor the current through it change. If you are talking about how a discharged capacitor voltage changes when it is connected...
  12. AnalogKid

    Would like some advice about my motor speed control circuit.

    A MOSFET is fundamentally different from a bipolar transistor in many ways. One of them is that it does not need external current limiting at its gate to prevent overcurrent damage. A series gate resistor can reduce high frequency noise generation in some switching power supply circuits, but...
  13. AnalogKid

    Common collector configuraton

    From post #14: Ic = Ib * hfe (3 * 100 = 300mA) Ie = Ib + Ic (300 + 3 = 303mA) ak
  14. AnalogKid

    Clean square waves using a 555 timer?

    Did you happen to measure the output rise time before and after the fix? ak
  15. AnalogKid

    Noise Activated Switch, with a Difference.

    And to be clear, there are many ways to solve the problem. One of them is a 6-pin or 8-pin PIC driving the SSR, with inputs from several triggers and the switch. All of the deciding and counting and other logic is in PIC firmware. So for this part of the project, would you rather solder or...
  16. AnalogKid

    Noise Activated Switch, with a Difference.

    Bored at work. This is a first pass at the lamp flasher. A positive pulse on the trigger input starts the three-or-four flash sequence. The lamp ends in the same on or off state it started in. Pressing the button toggles the lamp for local on/off control. Adjusting R1 changes the flash...
  17. AnalogKid

    Noise Activated Switch, with a Difference.

    Sounds like two separate projects, a trigger generator and a lamp flasher. To keep the flasher simple, I recommend a small relay or solid state relay (SSR) rather than growing a TRIAC switch circuit from scratch. Each half of a CD4013 dual D flipflop has direct set and reset inputs plus...
  18. AnalogKid

    78L33 regulator

    There is no resistor in either the datasheet or the schematic you posted. What resistor are you referring to in post #1? ak
  19. AnalogKid

    Appropriate Oscillator

    In your first post you mention the 555's 200 mA output current as a "limitation". Why? That is an exceptional output current for a small signal device. What output current do you need? Does your output need to only source current, like a single power transistor switch, or does it need to...
  20. AnalogKid

    Designing A Power Supply

    If you are limited to the non-HV version of the LM317, there are two options to get the output voltage range you want. Actually, three variations of the same option, a pre-regulator. Note that the input voltage range of the standard LM317 regulator is almost unlimited. It is the voltage...
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