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  1. KrisBlueNZ

    Piezoelectric Transducer Help

    Hi Jesse and welcome to Electronics Point :-) Unless you have an industrial piezo and you're pounding it with a sledgehammer thousands of times per second, you won't get enough power to overcome the battery's own self-discharge, let alone charge it to any useful voltage in any reasonable period...
  2. KrisBlueNZ

    Transmit and receive parallel data through radio link

    Don't worry, I haven't forgotten you! I'm still working on the design.
  3. KrisBlueNZ

    Boost converter 12V to 36V (25 mA load) using 555

    That's great! Well done! The MOSFET is not critical. Assuming you want a compact through-hole part, an excellent and very cost-effective option from Digi-Key is the Fairchild FQU13N10L at USD 0.71. Ratings are 100V, 10A, 0.18Ω, IPAK/TO-251AA package...
  4. KrisBlueNZ

    NE555 timer help (newbie)

    You're welcome. You could make a similar circuit with two 555s but my design will generate a more accurate display. Two 555s will oscillate at independent frequencies with no synchronisation, and frequency drift could disturb the display. You need many of the other components anyway...
  5. KrisBlueNZ

    Repair NASA Marine Echo sounder

    You'd better hope he still has the same email address (imaginations at ntlworld dot com) - that thread is 11 years old! (It's from a Usenet newsgroup.)
  6. KrisBlueNZ

    Repair NASA Marine Echo sounder

    Looks like the transistor is a Motorola / ON Semiconductor BDX33D: Darlington NPN, 120V, 10A. You should check it for short circuit - set your meter to resistance or continuity, put the red probe on the centre pin (or the metal tab at the top) and the black probe on the lead closest to the edge...
  7. KrisBlueNZ

    How to get a constant voltage output from a dc to dc converter?

    The problem is that the amount of energy you inject into the inductor on each switching cycle is constant. It is determined by the input voltage and the ON time of the transistor. Each time the transistor turns OFF, this energy is dumped into the output circuit. This causes a constant amount of...
  8. KrisBlueNZ

    How to get a constant voltage output from a dc to dc converter?

    So what do you want to do?
  9. KrisBlueNZ

    How to get a constant voltage output from a dc to dc converter?

    As Steve suggested in post #3, you need to add circuitry to monitor the output voltage and adjust the duty cycle of the control signal feeding the transistor so that the output voltage remains constant. There are various ICs available that will do this - for example the UC3842/3/4/5 series, and...
  10. KrisBlueNZ

    Twin LED Flasher

    Then the rabbi says, "Oy vey! Dis iss not a very funny joke!" Seriously Adam I think you need to focus more on presenting information that will be useful to the reader. These may be interesting thoughts, but to write a useful resource, you really need to ask yourself, "what questions are...
  11. KrisBlueNZ

    Yamaha PSR530 Keyboard, No Display

    Great! Well done :-)
  12. KrisBlueNZ

    [free energy] is there hidden power in plain sight?

    I forgot to mention: the thread title was the big clue.
  13. KrisBlueNZ

    [free energy] is there hidden power in plain sight?

    Then perhaps you didn't read the last paragraph. Or perhaps the punctuation abuse just made me see red!
  14. KrisBlueNZ

    [free energy] is there hidden power in plain sight?

    I have flagged this thread with "[free energy]" because you are talking about generating more power than you use. According to the current laws of physics, this is impossible; I assume you have made incorrect assumptions and/or miscalculations. We get free energy threads here from time to time...
  15. KrisBlueNZ

    NE555 timer help (newbie)

    Here's a circuit that should do what you want. It contains two ICs, as well as various small components. The ICs are from an old family called the CMOS 4000 series. These are still widely available and often used, especially by hobbyists. U1 is a CD40106B "hex Schmitt trigger inverter". It...
  16. KrisBlueNZ

    Twin LED Flasher

    Thanks for the compliment Adam :-) I only wish it were true! Well, conventional current is just like electron flow except in the opposite direction, so once you "know" one, you "know" the other. Conventional current fits better with the direction of the arrows in semiconductor symbols -...
  17. KrisBlueNZ

    Trying to fix electronics on elliptical trainer

    The "K" in the marking means ±10% tolerance. It really is a 0.5Ω resistor! (A 500Ω resistor would be marked "500Ω", and resistors that are marked in kilohms are marked with "KΩ" not "ΩK".)
  18. KrisBlueNZ

    NE555 timer help (newbie)

    There are a number of web-based EDA options around now that you can use to draw up a schematic of your LED connections. See http://spectrum.ieee.org/geek-life/hands-on/cloudbased-electronicdesign-tools-gain-traction for links to four of them. That article looks more like an advertisement for...
  19. KrisBlueNZ

    Impact switch/acceleration switch?

    Hi Will and welcome to Electronics Point :-) I've tried Digi-Key and Mouser, who are the largest resellers, and neither of them carry Select Controls products. It might be worth looking at their web sites - http://www.digikey.com and http://www.mouser.com - to see whether they have something...
  20. KrisBlueNZ

    Repair NASA Marine Echo sounder

    Hi Christian and welcome to Electronics Point :-) I doubt you will find service or technical information. We might be able to estimate the value if you post a photo of the top side of the board.
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