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  1. AnalogKid

    Two power sources

    Step 1, Leave Australia. When you are that far south of the equator, Maserati's turn to the left only. ak
  2. AnalogKid

    Tv on a boat.

    "Switched it off..." three times. - What is "it"? Was the TV turned of with the converter still connected and powered up? If so, what was the converter output voltage with no load? And, do you really think anyone can help with no more tech detail than "smell of burning..."? Make and model...
  3. AnalogKid

    convert 110v dc to 24v dc

    You can buy switching regulator modules that handle this input voltage range, or build one with a control chip fro Linear Technology. ak
  4. AnalogKid

    Convert +12V DC to -30V DC

    Maximum output current Minimum output current? Adjustable? Isolated? ak
  5. AnalogKid

    555 timer problem

    Although my post is brilliant, it is too succinct for its own good. Alec's post shows a differentiating network capacitor C1 and resistor R2, to shorten a long input pulse into a short triggering pulse. My post describes how to calculate C1 and R2 based on the output pulse width you want to be...
  6. AnalogKid

    Francis Deck Phantom Powered Piezo Preamp modification

    It is more of an impedance buffer than a preamp. The gain is slightly less than unity. If the two outputs are perfectly balanced, a single pot between them (after the coupling capacitors), wired as a rheostat, could reduce the volume to zero. That would inject more and more power supply noise...
  7. AnalogKid

    Standalone Clock

    Links to the components you are considering would help. ak
  8. AnalogKid

    555 timer problem

    The internal trip point for the Trigger input is Vcc/3. The time for the capacitor to charge up to this is approx. 0.4 x R x C. As long as this is shorter than the output pulse (I'd say 25% for margin), the output timing will not be affected. ak
  9. AnalogKid

    How much of a Short circuit is too much?

    You control the answers to all of your questions. First, how much heat? In watts or joules or BTU or temperature rise above ambient, only you know how much heat you want. Second, how big are the batteries? Once you know how much energy you need, you can determine if your batteries can supply...
  10. AnalogKid

    120/240ac Triac Dimmer

    Hmmm...we may be mis-communicating here. Scrambling now, will re-read later. ak
  11. AnalogKid

    120/240ac Triac Dimmer

    No. Not in this or any other known universe. Rewiring my entire house, and cutting open up and gutting all of my light bulbs so they work only with a custom-made lamp dimmer that does not fit in a wall box, and coming up with an adapter for every lamp socket in the house or replacing all of...
  12. AnalogKid

    120/240ac Triac Dimmer

    Barely. Why are LED bulbs ruled out?
  13. AnalogKid

    120/240ac Triac Dimmer

    "open up the led bulb," - No. These things usually are glued or ultrasonically welded, so opening up is a destructive process. It also *instantly* invalidates all safety certifications. Dimming is done on the AC side because that is where is it the most convenient, safest, and lowest cost for...
  14. AnalogKid

    Help needed with rocket timer circuit

    There are many different ways to combine a couple of transistors to do this task. Two NPN, two PNP, one of each, small MOSFETs - all work approximately the same way. It depends more on what you have than any "right" way. Usually I try to minimize the number of different components, so I would...
  15. AnalogKid

    Help needed with rocket timer circuit

    It sounds like he says printed circuit boards are more trouble than they're worth, then offers to sell you one. For "any good PNP transistor" there are at least two different pin assignments. Without the part numbers and datasheets for the transistors and SCR you are using, there are no...
  16. AnalogKid

    Help needed with rocket timer circuit

    Perhaps a word or 50 about what the circuit is supposed to do might help figure out if it is doing it. Simple stuff like - Is the circuit in the rocket or on the ground? What is the desired timing range? What is the "load"? Does the timer need to be adjustable? ak
  17. AnalogKid

    DC Power Supply - Choke for regulated power supply

    18 Vrms, after a full wave bridge and at only 200 mA, will be close to 24 Vdc. A 1000 uF filter capacitor will be more than enough to keep the negative peaks of the ripple voltage above the required minimum input voltage for an 18 V regulator. ak
  18. AnalogKid

    Thermistor ID

    What is a Bose PS51? How old is it? Which thermistor? In what part of the device is the failed thermistor located? Did it split down the middle or fly apart? What shape was it before it failed? What color was it before it failed? Are the leads staggered or inline? Is there a logo on the part...
  19. AnalogKid

    pcb

    On the page there is a link to a folder with the Gerber files. These are the image files you send to a pc board house to make the bare board. Also, there is a link to another page with a schematic, but it is not clear if this is the exact schematic for the board that is shown. Between these...
  20. AnalogKid

    pcb

    You can't. As explained to you in the other forum, if you have only one image with two pieces of information, both will be in the result. Please post a link to the article with the drawing. Please post an image of the drawing or a link to the image file. Please provide some useful...
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