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  1. Herschel Peeler

    Peltier

    You got a good one. Mine never got hot enough to cook with or cold enough to make ice but it kept my coffee cup warm or my sodas cool.
  2. Herschel Peeler

    Peltier

    Instructions usually come with it. Not knowing specifically what you have advice is difficult. Mine is pretty straight forward. Red and black wires are positive and negative. Draws about 6 Amps. Be sure to use a heat sink on the hot side. Fans on both sides are a good idea. For power I used an...
  3. Herschel Peeler

    Running LED - all LED turn ON when reach the last LED?

    Clue: Diodes
  4. Herschel Peeler

    Powering 104 LED's from Molex connector, possible?

    Theories aside, what voltage do the LEDs actually drop across them at the 20 mA, or whatever you intend to run them at? Can you run 4 in series from 12 V? The difference between 1 ohm and no resistor at all is minimal,.Yes, good designs should have a resistor. That being said I have a flashlight...
  5. Herschel Peeler

    hardware learning

    Bipolar junction transistors. NPN to start.
  6. Herschel Peeler

    hardware learning

    I don't know what stuff is available in India. We will find out as we go along. Do you have any specific interests in mind for circuits. Analog? Digital? Microprocessor? Practical circuits? Educational circuits? Let's start with some classroom basics and see if they fit your expectations. Diode...
  7. Herschel Peeler

    hardware learning

    It would help me specify parts if I knew what you had available. Local is good. Are you in Seoul? Electronics Market? Great place. Everything available at good prices there.
  8. Herschel Peeler

    hardware learning

    Good start. How are you set up for power sources? How are you set up for components? Where do you normally buy parts from? I will see if we can stay coordinated on these things. Me? I am a retired tech school teacher. I, literally, have hundreds of wall wart power supplies for projects and a...
  9. Herschel Peeler

    hardware learning

    PDF file okay? Design 629. + and - 12 V with two variable voltage sources. As a simpler option you can just use + and - 12 V in batteries. This gives you a suitable + and - V for op amp exercises and a variable +V to - V at 100 mA or more for other exercises. Do you have a breadboard and multimeter?
  10. Herschel Peeler

    Information for a complete beginner

    Too complicated? Nonsense. It looks like a good starting circuit. Just start building it piece by piece. If this is what you want to do I think we can step you through building it section by section.
  11. Herschel Peeler

    hardware learning

    Power supplies are a good place to start since later projects will require a power source of some kind. A breadboard is a good start, building circuits on a breadboard powered by a power supply. 5 Volt power supply, about 300 mA or so is good. +12 and -12 V power supply for op amp circuits, 100...
  12. Herschel Peeler

    Heating Jacket controlled by Arduino for Winter

    Well 3 V at 1.5 Amps for three hours is what your battery will supply. You are going to need a lot of batteries. 10 elements means 10 batteries.
  13. Herschel Peeler

    DC offset of OPAMP

    Single power or dual power rail? Yes, cap coupled. DC offset design depends on which op amp you are using.
  14. Herschel Peeler

    Heating Jacket controlled by Arduino for Winter

    I don't think a microcontroller is called for, unless you just want to use a microcontroller. Yes the PWM suggested is good. Just one area to be heated? Washable or removed before washing?
  15. Herschel Peeler

    LED's and constant current

    Re: "I fired it up again and noticed that a couple LEDs are not as bright as the others" That sounds like you over stressed the LEDs.
  16. Herschel Peeler

    LED Signal Dummy load

    Why not just use a switch instead of all the circuitry? Maybe I am missing the details of how your current operated relay works. All relays are current operated. Yours draws 300 mA when operated from 110 V?
  17. Herschel Peeler

    Modify circuit

    So remove switches B, C and D, and jumper across where switch D was.
  18. Herschel Peeler

    Needing help with a 555 timer switch

    Is the 555 retriggerable? I don't think so.
  19. Herschel Peeler

    Needing help with a 555 timer switch

    Both Reset and Trigger are active low inputs. They never go low in the circuit, If Reset and Trigger both go low at the same time will it ever trigger?
  20. Herschel Peeler

    Common Base

    Not that it is really relevant to your question,, just because it is a nice place to mention transistor characteristics ... The data sheet for a 2N1711 gives the following info on the gain of the transistor. hFE = 20 (@ IC = 10 µA) hFE = 35 (@ IC = 0.10 mA) hFE = 75 (@ IC = 10 mA) hFE = 100 to...
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