On 16 Nov 1996 19:07:05 GMT, jaz321@aol.com <jaz321@aol.com> wrote:
>  I'm a novice trying to learn a few things on my own.  I want to try to
>make my own circuit board.  I need a simple plan or schematic to show how
>to make a LED blink.  I have many capacitors, transistors, resistors,etc. 
>I would probably use a 9-volt battery to power it.
You can use the following circuit to flash two leds alternatly.

        +--------------+---------------+--------------+---- +3 to +9 volts
        |a             |               |              |a
        D1             R3              R4             D2
        |c             |               |              |c
        |              |               |              |
        R1             |               |              R2
        |              |               |     +        |
        |              +---------------|------C2------+
        |       +      |               |              |
        +-----C1-------|---------------+              |
       c|              |               |              |c
         \ b           |               |           b /
      Q1  |------------+               +------------|  Q2
         /                                           \
       e|                                             |e
        +---------------------------------------------+----- Gnd

R1,R2 220 ohms
R3,R4 100k ohms
Q1,Q2 any NPN  2N2222, 2N3906, BC108, etc
D1,D2 LEDs
C1,C2 22uF increase to slow flash rate

If you want to only flash one LED replace the other with about and diode.

If you want to use pnp transistors just switch the positive and negative
from the battery, flip polerized caps and turn the LEDs around.

You may want to go to radio shack and buy one of their electronics books.
They have many little circuits like this one and some describe the basic
fundaments of electronics.

 Brian Mihulka                            "A lot of people are afraid of
 bmihulka@engrs.unl.edu                   heights. Not me. I'm afraid of
 "http://engrs.unl.edu/~bmihulka"           widths"       -- Steven Wright
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Date: 18 Nov 1996 07:29:00 GMT

Original Subject: Re: need a simple schematic

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