Home made components

Discussion in 'General Electronics Chat' started by boriz, Aug 2, 2009.

  1. boriz

    Thread Starter New Member

    Jul 16, 2009
    Hi all.

    Some of you will remember the cat’s whisker. (So far as I understand, a home made diode). Tesla coil builders commonly make their own spark gaps, coils and capacitors. I’m wondering what other components could be handmade or improvised.

    Anyone with experience or tails to tell, please post. Pictures would be good.

    To start the ball rolling...

    As a kid, playing games on my BBC micro. I stole a joystick from an old ‘pong’ type TV game. I discovered quite by accident that the only way to get it to work was to hold my finger on the back of the joystick circuit board, bridging two contacts. I can’t remember my thought process at the time, but I managed to get it working by pulling a leaf from one of my mother’s potted plants and wedging it into the gap. Every couple of days, I stole a new leaf. It worked just fine :)

    I didn’t know it at the time, but I guess I was making a pull-up resistor or something like that.
  2. rspuzio

    Active Member

    Jan 19, 2009
    > I’m wondering what other components could be handmade or improvised.

    If one has the equipment and motivation, one can make quite a variety of components
    at home. For instance, here is someone who makes his own transistors and IC's:


    Of course, at that point, making the components becomes a passtime
    in itself, not a practical way of obtaining components. As for components
    which are easy to homebrew and for which homebrewing is a practical
    way for the electronic hobbyist to obtain those components, here is what
    I can think of:

    Inductors (including transformers and electromagnets): Since it's basically a
    matter of wrapping wire around a spool, these get homebrewed all the time.

    Capacitors: As you mention with the Tesla coil people, high voltage capacitors
    often get homebrewed. Also, here is a description of how to make a good old
    air variable capacitor:


    Resistors: One can make custom resistors in small values from resistance
    wire. For high power ratings, water resistors can easily be made at home
    from plumbing parts.
  3. flat5

    Active Member

    Nov 13, 2008
    You can make resistors from pencils.

    Even more fun is to put a dc bench supply output across a pencil and watch the graphite get red hot and the wood to catch on fire.
    Too much voltage and the "lead" breaks before the fire can happen.
  4. yourownfree

    Active Member

    Jul 16, 2008
    I learned how to make a precision resistor from a resistor(carbon type) by filing it down while watching the meter until you get the exact reading you want. Start off with one close to what you want. You know I wonder if you could take a small non conductive tube and fill it with pencil graphite then force a wire with a small plate attached and shove in the hole and compress it, then JB Weld it in place.
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    There's always aluminum foil and waxed paper capacitors (low voltage only, please).

    If you have carbon granules such as were used in the mouthpiece of Ma Bell's phones, they make a variable resistor that changes with applied pressure.
  6. scythe

    Active Member

    Mar 23, 2009
    If anyone homebrews their own diode or transistor, my hat goes off to you!

    edit: I just saw that link to flickr. All I can say is "wow".
  7. Wendy


    Mar 24, 2008
    Jeri Ellsworth

    I think I know that lady's name. Don't know her personally (but would like to). She is big in the Commdore Computer community, where she has made several related projects, such as a C64 on a chip. It was a commercial project. You could buy one in a joystick handle, a lot of people figured how to take the pins off this chip and interface it to the various devices such as a keyboard and it's serial buss (old school) for the floppies and hard drive.

    Trust me, this lady's brains put her on the uber sexy scale for anyone even mildly geeky.
    Last edited: Aug 4, 2009
  8. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    Here's a guy who makes his own vacuum tubes ("valves" to some). The video has been around for quite awhile, and although it is in French, it is obvious what he is doing.