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  1. BobK

    Battery advice for size and weight sensitive project

    Batteries are rated in maH or milliamp hours. That translates to the number of milliamps you can draw and expect the battery to last an hour. Draw half that, and it will last 2 hours, etc. Your battery needs to be at least 4.5V, so 3AAA or AA primary cells (non-rechargeable) would just...
  2. BobK

    Weapon worries...

    Yes, but he did not draw the little hysteresis loop inside each NAND gate. Bob
  3. BobK

    can someone please help with this maths calculation for torque?

    It says: "Torque constant of 0.0355N.m/A" Which means for each Amp you get 0.0355 Nm of torque. So, at 3.5A you get 3.5 x 0.0355 = 0.1245 Nm. Which is about half the rated torque. Bob
  4. BobK

    Inverter problems please help

    Cool. I am impressed. Now would be a good time to install a proper switch so that this will not happen again. Bob
  5. BobK

    help needed on first project, led counters with key reset

    You also need a crystal clock divided down to one tick per day. And seven segment decoder / drivers. You are talking about a handful of chips or one 28 or 40 pin micro and a few transistors or uln2004. Bob
  6. BobK

    Possible solutions to figure out the configuration of the preamp with this microcontroller

    If you mean how can the microcontroller detect how many preamp boards are installed, that is trivial. You simply need one connection on each preamp connector that the preamp board will ground when installed. This line will be attached to an input pin on the micro and have a pullup (internal to...
  7. BobK

    Modifying a led strip circuit

    The LED strip itself will stay on continuously if powered continuously. You need to eliminate the controller and simply supply the correct voltage to the LED strip directly. Do you know the voltage? It is probably 12V but you would want to confirm that first. Bob
  8. BobK

    How ic fabrication is done?

    However, if you have about $1B, you could build a fab. You could probably pick up one that was going out of business for $100M or so. From wikipedia: https://en.wikipedia.org/wiki/Semiconductor_fabrication_plant Bob
  9. BobK

    Charging Issue

    Off topic I know, but let us know how it goes when you go through customs carrying a drone. Could be interesting. Bob
  10. BobK

    Noob needs help building a circuit board

    What AK said is true of analog amps, but class D amps can do much better. They can swing to nearly ±5V with little power loss to heat. That is about 1.5W into an 8Ω speaker. Bob
  11. BobK

    How ic fabrication is done?

    About 6 years of school. Number of BJTs - 0 Number of MOSFETs- up to billions Bob
  12. BobK

    Noob needs help building a circuit board

    I doubt you can build it as quickly or as cheaply as you can get it on Ebay or Amazon. There are plenty of vendors even on Ebay who ship in the U.S. In fact, you will not be able to buy the 18650s for less money than you can get a power bank. If they are less, they are likely counterfeits...
  13. BobK

    How ic fabrication is done?

    The are designed by people sitting in cubicles using CAD programs. The are manufactured by a many step photo-etching process in which different layers of doping material and metals are deposited on pure silicon wafers in a clean room. Bob
  14. BobK

    Can anyone ID this inductor and the manufacturer?

    Now that you can see the wire size, it is certainly μH instead of mH. Bob
  15. BobK

    Project Design Please Give Me Some Suggestion

    Now you did it. I showed the lovely wife Morticia the video, and she, being a avid gardener, is now demanding that I make one for her. She even asked in French! Bob
  16. BobK

    Integrated Circuit Chip Help

    It is not likely that the circuit you found uses a bunch of discrete parts to do what an op amp will do. Op amps are pretty much the swiss army knife of analog electronics and anyone designing such circuits in the last 50 years would be familiar with them and choose to use them instead of...
  17. BobK

    Finite state Machine

    Tic-tac-toe Bob
  18. BobK

    Ltc 3780- 12v 10 amp input

    Iout = Iin * Vin / Vout * e Where e = efficiency < 1 Bob
  19. BobK

    Simulating a circuit which has an ATmega328, is it a waste of time?

    I tend to simulate the analog portion of a circuit by using LTSPICE. It it is driven by a micro, I make a voltage source that simulates what the output of the micro should look like. Bob
  20. BobK

    Powering my IC

    The current used by the CMOS chip will be negligible compared to that used by the LED. Bob
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