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  1. Herschel Peeler

    I am to design a switched mode psu without IC components.Help please

    Good. Build and test the same way, stage by stage. Sid you say the teacher wanted you to do simulations before building? That is good procedure. Design then simulate stage by stage as you go along.
  2. Herschel Peeler

    I am to design a switched mode psu without IC components.Help please

    Such is the objective of a school; theoretical to practical. So starting ... what do most switching regulators have in common to their design? We have an oscillator whose leading edge sets a flip flop. rthr flip flop is cleared by a "good voltage" signal of some kind. The output of this flip...
  3. Herschel Peeler

    I am to design a switched mode psu without IC components.Help please

    I am not suggesting you use the I. Only get an idea of what stages are in the switching regulator and some possible designs. Are you taking a class you are not ready for?
  4. Herschel Peeler

    Zeroing out a LM317 reference voltage with a zener - PSU build

    Thanks for the editing. I didn't think pdf documents would be a problem. And yes, output down to zero volts. Trying to move the reference down to -1.2 Volts instead of ground.
  5. Herschel Peeler

    I am to design a switched mode psu without IC components.Help please

    Take a look at a data sheet for any switching regulator. That will give you an idea of what stages you need and a general design. Rectify the line voltage. Chop it up at some desired frequency, run it through a transformer. Transformer secondaries provide the desired voltages at certain...
  6. Herschel Peeler

    Zeroing out a LM317 reference voltage with a zener - PSU build

    Is this what the original post was trying to accomplish? I haven't tried it yet. Might it work?
  7. Herschel Peeler

    Zeroing out a LM317 reference voltage with a zener - PSU build

    Ah!
  8. Herschel Peeler

    Zeroing out a LM317 reference voltage with a zener - PSU build

    Re: "Unfortunately, there is no simple way to obtain the negative voltage..." The original post shows a second power supply doing nothing. think the intention was to use this as the negative supply. My method was to was a 7660 voltage inverter but it throws off the 1.25 V reference circuit of...
  9. Herschel Peeler

    "Lightpole" Project

    Nothing wrong with that reasoning. Not having a specific idea of how these switches are used in the play of the game flexibility is a good idea. Using a microprocessor would you keep the counters external, as suggested and just make the controls programmed? I don't know the capabilities of the...
  10. Herschel Peeler

    "Lightpole" Project

    All good ideas
  11. Herschel Peeler

    "Lightpole" Project

    Okay, first shot ... Design 592 We have two 5-digit counters, “A” and “B”. They reset on power up or by pushing a Reset switch. We have a three position toggle switch, center off, momentary in the up “a” or down “b” position. The switch must be held in the “A” or “B” position for at least 5...
  12. Herschel Peeler

    "Lightpole" Project

    5 digit counters? Keeping count of seconds for up to ten hours comes up to a maximum of 36,000 seconds. Then you are looking at a box about 4" x 6", 3" deep.
  13. Herschel Peeler

    Zeroing out a LM317 reference voltage with a zener - PSU build

    Is the circuit missing a wire from the Zener to the negative supply? this is the option I used. No extra supply was needed. I used a 7660 to generate the -V.
  14. Herschel Peeler

    "Lightpole" Project

    The counters display a reading in seconds? What should be the maximum count? One pole with a white and a green lamp inside? One three position switch, center off. if the switch is held in one position for 5 seconds one light comes on. The counter keeps counting. If the switch is moved to the...
  15. Herschel Peeler

    Linear Power Supply Help!!!!

    How much current do you need? The transformer and rectifier must be able to deliver these needs. LM317 and 337 can be added to the previous schematic easily. Fused? Circuit breaker? Electronic fuse? Something is suggested especially for a classroom. A single supply that does it all or various...
  16. Herschel Peeler

    "Lightpole" Project

    How big are the poles? How bright of a light? Can you provide a picture of an example? I can find pictures of airsoft events but nothing with such lights. Does it have to be disassembled and portable?
  17. Herschel Peeler

    How can I design a multidrop connection for TTL serial communication?

    Other consideration ... synchronous or asynchronous? How many lines? One Data line or two (Data In, Data Out) Strobe? Reset? Sync? Address? Some standard interface like I2C?
  18. Herschel Peeler

    Hello, Welcome! (Introduce yourself)

    Small world. Another one from Nevada. Las Vegas here.
  19. Herschel Peeler

    2 transistor circuit input output question.

    Unnecessarily complicated. The 5K and 20K make a voltage divider that puts the base at9mV. For outputs A and B to be the same the other base must also be at 8 V. If the bases are at 8 V the emitter must be 0.7 V below that.
  20. Herschel Peeler

    Question about Li-ion batteries

    If they were all the same model and in the same condition it would work.
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