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  1. BobK

    Is the following a universal gate?

    Where is the definition of basic gate that you are using? Bob
  2. BobK

    Pedal powered generator

    We are too easy on the kids today. Charge a phone? That's for a weakling sissy. How about toasting a slice of bread? Bob
  3. BobK

    Understanding N channel and P Channel FETs

    Thanks, now I understand. Bob
  4. BobK

    Variable time on/off switch circuit, for model tree-house project

    D cells would get you to about 3 days constantly on. A more sophisticated timer, one that allowed you to turn the lights on only during the open hours of the exhibition, would do it. Ideally, the timer would run off the 4.5V battery and use an electronic switch rather than a relay. Not sure...
  5. BobK

    Is the following a universal gate?

    I am referring to Ratch saying some of them are basic and others are compound. I am disagreeing with that. Bob
  6. BobK

    Variable time on/off switch circuit, for model tree-house project

    Is the timer module using a relay? If so, that is using all the power. How about posting a link to it. Bob
  7. BobK

    Interface microprocessor with microcontroller

    An X86 chip communicates with the outside world through memory mapped I/O. You would have to decode a memory address to know that a read / write was intended for the microcontroller and supply / accept the data when it is accessed. Hopefully you realize that the X86 chip will need external...
  8. BobK

    How to use DC power supply to power AC powered appliances?

    An inverter is a circuit that converts DC to AC. If you build a "DC to DC inverter" it is a DC to AC inverter followed by a rectifier. So just leave off the rectifier. Bob
  9. BobK

    Is the following a universal gate?

    I see no reason to exclude any of the 16 possible two input, one output gates as non-basic. Bob
  10. BobK

    Understanding N channel and P Channel FETs

    What I am saying is that I cannot understand the why an N-channel MOSFET is called enhancement mode and an N-channel JFET is called depletion mode when, in both cases, raising Vgs increases the current in the channel. In both cases there is a threshold voltage, and when Vgs is below Vgsth...
  11. BobK

    Understanding N channel and P Channel FETs

    That does not make sense to me. Higher source to gate voltage produces more current. That sounds like enhancement. The difference is that the gate threshold is below zero. Bob
  12. BobK

    74LS245 it doesn't work like i think

    Whiskey Tango Foxtrot is WTF in international phonetic alphabet (Alpha, Bravo, Charlie...) Waltz Tango Foxtrot is my takeoff of that, as a ballroom dancer. BTW: The guys in the picture are certainly not doing any of those three :) Bob
  13. BobK

    74LS245 it doesn't work like i think

    To me, this means Waltz, Tango, Foxtrot (and yes, the lovely wife Morticia and I do them all, but Tango is her favorite.) Bob
  14. BobK

    Output Transitor Circuit Inconsistencies

    Try reversing the leads of the ohmmeter and make the measurements both ways. The measurement includes a semiconductor junction which will conduct with the leads in one direction, altering the measurement. Bob
  15. BobK

    74LS245 it doesn't work like i think

    What does the darasheet say? Bob
  16. BobK

    Is the following a universal gate?

    What nonsense. Apparenty, You can have an inverted outout, but not an inverted input. A NAND gate is basic, but if I remove the inverter on the output and put inverters on the two inputs it is no longer a single gate even though it implements the same function with the same circuit and all...
  17. BobK

    Is the following a universal gate?

    There are only 16 possible boolean functions of 2 onputs and 1 output. FPGAs implement all of them, so this is a gate that is a basic gate in some implenentations. Bob
  18. BobK

    Is the following a universal gate?

    Put a black box around it and call it a gate. I think you are being overly pedantic. Bob
  19. BobK

    Is the following a universal gate?

    I think we need a definition of "universal gate" to resolve this dispute. To me, it means a gate that any other gate can be made from a circuit using only instances of that gate. By that definition it is a universal gate. Bob
  20. BobK

    Starter Project: Camera and Live Feed

    If you wanted to learn mechanical engineering, would you start by designing a car from scratch? Bob So, are you going to start with sand? Bob
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