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  1. hevans1944

    Complete the circuit!

    This is homework, right?
  2. hevans1944

    2 transistor circuit input output question.

    Current is flowing in the same direction through both resistors and the base.
  3. hevans1944

    what am I

    Your Dekapot will last forever. Just make sure you don't exceed its input voltage limitation and (for best accuracy) use a very high impedance load on the output. Your 4-1/2 digit multimeter probably loads it enough to cause a one or two digit "error" in the divider ratio, which is probably...
  4. hevans1944

    2 transistor circuit input output question.

    But you did neglect the base current, iB, when finding the equivalent circuit. You assumed there was no base current and calculated the Thevenin equivalent for the junction of the two bias resistors. If there were significant bias current, compared to the current through the bias resistor...
  5. hevans1944

    garage door opener

    As well he should. This horse is dead, so let's quit beating it. Hi yo, Silver! (fade in 1812 overture)
  6. hevans1944

    2 transistor circuit input output question.

    That would be the parallel resistance of 5 kΩ and 20 kΩ. When calculating the Thevinin equivalent of the bias circuit at the base, you assume there is zero impedance in the 10 V voltage source which, along with the ground, means the two resistors are effectively in parallel. Base current is...
  7. hevans1944

    Interfacing between Little and Big endian

    Go look at some of the pages from this Google search. It refers to the byte order of byte-addressable random access memory when representing integers that require two or more bytes. The Wikipedia article gives a pretty clear explanation. You can blame the confusion on Intel who used the little...
  8. hevans1944

    garage door opener

    Au contraire, Ke-mo Sah-bee! Maximum smoke evolvem from motor, not connecting wiring. I suggest using this fine-stranded ultra-flexible 4 AWG welding cable.
  9. hevans1944

    garage door opener

    But with the OP's design paradigm, a fuse would prevent the motor from obtaining maximum smoke and perhaps spectacular combustion. The proposed design could benefit from an unenclosed BA knife switch, IMHO. The exposed knife-switch terminals with #4 welding cables attached (minimum size for...
  10. hevans1944

    Help optimizing byte compare algorithm

    @chopnhack: ASM doesn't have to be unstructured programming. And, yes, it is difficult until you get the hang of it, which requires an intimate understanding of the underlying hardware. At some point the Intel microprocessors became so complicated that I found it impossible to program them, even...
  11. hevans1944

    garage door opener

    This is a Permanent Split Capacitor or PSC motor. The capacitor is always connected across the "run" and "start" windings, which are identical in construction and share a common connection (the white wire); power is applied between the white wire and either (but not both!) of the of the...
  12. hevans1944

    DC short circuit calculation formula for copper busbar

    You have been given some good advice and a reference by @Harald Kapp but you have provided no information on why you need to calculate the short-circuit current in the bus bar. You know the copper bus bars are capable of providing a 38000 ampere current to your process. They are certainly...
  13. hevans1944

    garage door opener

    "Do you feel lucky?" Ah! The pioneering spirit that made this country great lives on! No degrees necessary to participate and learn here. Experimentation encouraged. Your garage door motor has a largeish non-polaraized electrolytic capacitor labeled "motor starting capacitor" which terminology...
  14. hevans1944

    garage door opener

    If the ladder diagram offered by @Tha fios agaibh does not make any sense to you, then you are totally unqualified to re-purpose your garage door opener. Seek the services of a licensed electrician before you set something on fire. Given your statements that (1) the motor turns in one direction...
  15. hevans1944

    dc motor questions

    Your requirements are too vague. You need to be much more specific. How fast does the motor revolve (RPM)? What is the mass of the offset weight that causes vibration? What is the radius of gyration of the offset weight? How is the motor vibration coupled to a load, and what is the mass of that...
  16. hevans1944

    Heathkit IP20 Power Supply

    Séance, anyone?:eek:
  17. hevans1944

    Volts to ohms for fuel sender

    Or a young passenger riding on the tank. So, never mind! Tank rucksacks or tank saddlebags are common accessories.
  18. hevans1944

    Steam Hood - Electronics Connecting

    We only use dots here on schematics, and you have only provided pictures of components. Looks to me like you need a wiring diagram. Do you have a manufacturer's name and model number? Have you tried to contact the manufacturer? Do you know anything about electricity?
  19. hevans1944

    Half dozen of one, 6 of the other.

    You forgot to include the voting thingy at the bottom when you created this thread. Ah say toe-mate-toe. If en y'all want to say toe-motto, well that's on you.:p
  20. hevans1944

    Confused with a contactor

    It appears to be a "special" terminal strip. Some of the adjacent terminals appear to be internally connected together: R and T; T and R; 6 and 5 reading from the top down. Note the placement of the test prod holes. Power it down (un-plug the line cord) and check continuity to be sure. It...
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