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  1. hevans1944

    LM317 2N3055 Variable Circuit Problems

    OMG! Here I am at 72 thinking, "Just a few more years, Hop, and you kin be purrphekt Just keep on keeping on." Now you come along and tell me, "Nope. Takes a little while longer." <sigh> If I were forty again, and knew then what I know now, I would change a few things. Things were exciting in...
  2. hevans1944

    Tweaking an industrial ozone generator help (HV)

    Corona discharges are fun to play with. Perhaps the simplest solution to reducing the ozone production is to reduce the area available for the corona discharge. Maybe remove one of the two ozone-generating plates to reduce it by half and then attach some Teflon sheet material over some of the...
  3. hevans1944

    Power Dissipation in a simple circuit

    However, a verbose description will improve your English language skills and can be used as an adjunct description of the circuit schematic. Although some of us here are somewhat challenged in sketching and posting schematics, please make the effort. A simple pen and ink drawing on white paper...
  4. hevans1944

    Locking cat door, really need some help...

    You could, of course, sense the sudden increase in current that occurs when the motor stalls, and use that event to turn off the motor. A few turns of wire around a Hall sensor will do that. Timing the lock-time required, and using energy storage in a capacitor to un-lock seems simpler. Could...
  5. hevans1944

    I need a really small, really smooooth motor...

    If you are using the aluminum disk as an optical "light chopper" and perhaps modulating a weak optical signal to allow its synchronous detection with a box-car integrator or a lock-in amplifier, you need a really constant rotation speed. The best way I know of to get this is with a synchronous...
  6. hevans1944

    LM317 2N3055 Variable Circuit Problems

    Congratulations, Grand Pa!
  7. hevans1944

    Locking cat door, really need some help...

    Cats are smart. Teach your cats how to read and then put a little electronic display panel on the door. Display a message during the cleaning cycle: OUT OF SERVICE USE KITCHEN FLOOR. Or, if you do modify the cat door to lock during the cleaning cycle, perhaps the cats will figure that out for...
  8. hevans1944

    Designing a Time Delayed Relay

    I will look at this later... gotta go look for a possible new home Tuesday!
  9. hevans1944

    Understand VCO

    It appears that your lack of understanding of op-amps might be part of the problem. Many years ago, in the 1960s, when I first encountered operational amplifiers and negative feedback circuits, I had a difficult time trying to understand what was going on. Then one day I ran across a simple...
  10. hevans1944

    Help with PIR

    Post a link to the original blog. I have several PIRs salvaged from outdoor flood lamps that I was intending to use with a low-voltage DC supply, but pretty much abandoned the idea when cheap home security and hobbyist types became available. I recently purchased one of these from Radio Shack...
  11. hevans1944

    Diodes purpose in this circuit?

    You need to protect the inputs of the ADC in the MCU from overshoot, caused by possible parasitic LC ringing in the inductance of the motor winding. High-speed reverse recovery Schottky diodes are necessary because of the high frequency pulses associated with PWM motor current. Not much current...
  12. hevans1944

    Understand VCO

    There is a problem with the following explanation, copied from the OP's link: "The second op-amp is a Schmitt trigger. It takes the triangle wave as input. When the input voltage rises above the threshold of 3.33 V, it outputs 5 V and the threshold voltage falls to 1.67 V. When the input...
  13. hevans1944

    PC Audio Wiring Assitance Help.

    I like these, as made by Ideal (and others), because they close down to a precision-diameter circular hole, cutting through the insulation without nicking the wire. They come in two varieties, one for stranded conductors and one for solid conductors. Make sure you get the variety appropriate for...
  14. hevans1944

    PC Audio Wiring Assitance Help.

    They are called "keying plugs" and come in all sorts of varieties, depending on the connector. Most common for dual inline PCB connectors is a little plastic plug that slips into a female socket position, rendering that position unusable, but also making it impossible to insert the connector...
  15. hevans1944

    Electric Guitar Ampenstein

    Can also use a magnetron to brick credit card magnetic stripes. No high-voltage necessary.
  16. hevans1944

    PC Audio Wiring Assitance Help.

    Ace (The Handyman Place) Hardware sells shrink tubing at exorbitant prices, but if you need it... Also auto parts stores like NAPA and AutoZone and many others, but eBay is probably the cheapest if you can tolerate the wait for it to arrive.
  17. hevans1944

    PC Audio Wiring Assitance Help.

    It's desirable to cover it with shrink tubing just slightly larger than the bare twisted wire, and push this tubing up under the outer jacket after shrinking it, before attaching the end of the wire to a connector pin. You can leave the shrink tubing a few millimeters longer than the wire (it...
  18. hevans1944

    PC Audio Wiring Assitance Help.

    Rich, I agree 100% with Chris: the missing "heavier black wire" is actually the foil-shield "drain" wire, the "loose bare strands" you discovered. And, yes, you do need it. It forms the "common" connection for all the audio channels. A foil-shield is actually two layers, an inner aluminum foil...
  19. hevans1944

    Solar panel help!!!!

    That will work! I had a Bell Jar hoist that worked like that, but single chain only. Make sure you bolt to both chains to prevent binding. And I would prefer that you purchase a steel bar instead "going to have a steal bar".:eek: Or maybe even use some aluminum angle stock. Easier to work with...
  20. hevans1944

    Help finding a suitable transformer

    Well, you are self-described as "Electronicnewbie" so what was so patronizing about my response? You didn't even bother to answer my questions! I was practicing my patronizing skills. Maybe we both have that down pat. Maybe the OP will deign to reveal WTF he is trying to do. No, you didn't...
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