Re: using breadboards

will do. wire rap sounds like what I may need, though.
  ----- Original Message ----- 
  From: Dale Leavens 
  To: programmingblind@xxxxxxxxxxxxx 
  Sent: Sunday, February 22, 2009 2:12 PM
  Subject: Re: using breadboards


  Oh no!

  Your 120 volts are alternating current. You don't reduce alternating current 
voltage with resisters. you usually do that with a transformer. Then you need a 
rectifier to convert the alternating current to direct current. These days you 
can probably buy that on a chip with other circuits. The direct current 
shouldn't have to be all that smooth for charging batteries so you likely 
wouldn't need much if any of a smoothing circuit and the rectifier chip these 
days will probably already have spike limiting circuitry, I am really out of 
touch with modern solid state technology.

  You probably wont be wanting to do any soldering, it is possible for blind 
people to solder electrical connections and I have done a certain amount of it 
but soldering those little and closely spaced chip pins is difficult and many 
can damage easily if they get over heated.

  There is a bread boarding technology called wire wrap, or at least there was. 
This takes advantage of the fact that most digital chips have square pins with 
fairly sharp edges. There is a little device which looks a little like a screw 
driver except that it is hollow. You feed the wire through a hole, fit the tube 
over the end of the pin then twist it a couple of times to wrap the wire around 
the pin. The sharp edges of the pin cut into the insulation of the wire making 
electrical connection and the wrapping holds the wire reasonably securely. this 
is not probably the ideal way to build permanent circuits because the 
connections wont be as strong as soldered connections however for test circuits 
or other temporary fabrication it is a good compromise and quick. It is 
probably 25 years ago since I did any thing with wire wrap, I don't know if it 
is still available.

  Before you go plugging anything into the wall though I very strongly 
recommend you learn a whole bunch more about electronics theory.


    ----- Original Message ----- 
    From: Tyler Littlefield 
    To: programmingblind@xxxxxxxxxxxxx 
    Sent: Sunday, February 22, 2009 3:06 PM
    Subject: using breadboards


    Hello,
    I'm looking to start using breadboards to create some small things.
    I'd like to start off with something small, possibly a battery charger or 
something similar.
    I found a small tutorial on instructables, but not totally sure how to get 
going.
    It explained how things work somewhat, but not accurately enough for me.
    It mainly used pictures to explain, which didn't do me a whole lot of good.
    Any ideas on how I can set this up?
    I understand the polarity--hooking one negative end to the positive etc so 
that the circuit forms a loop, I'm just not sure how to do what I want.
    So, here's my idea.
    If I figure out the layout, I can set up a power cable going from the 
outlet to the breadboard.
    Then I can place in jumpers to bridge the gap.
    I can take the 120 volts down to 9 with some resisters (?) and hook a 
battery pack to the other end that will charge the batteries.
    I'm thinking I'm way off, but... ideas would be great.
    If I could, I'd like to set it up so it'd charge like 4 at once, then I 
could cut down the 120 to 36. Possibly put in a heat sink to keep it from 
getting really hot.

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