# Where to start

Discussion in 'Electronic Basics' started by [email protected], Mar 8, 2005.

1. ### Guest

Hi,

I am a complete newbie when it comes to electronics. Now that I have
thrown that out there, I was wondering if someone could help point me
in the right direction.

I would like to build (what I assume to be) a very simple system. It
would basically be a wire with an LED on each end of it. I'd like each
LED to be a button (or have a button nearby) that when pressed both
LED's would light up. Ideally I would be able to use a very small
battery for this.

Could someone recommend a book, website, txt, tutorial, etc. that would
get me started on this?

Thanks for any help!

2. ### ExternetGuest

Hi.
Buy an electronics experimenter kit. It will provide enough
opportunities to learn in different ways; and they usually have well
Miguel

3. ### Robert MonsenGuest

You can get LEDs and buttons at electronics stores. You will also need
what are called resistors, which are little two-lead devices which limit
electrical current.

So, a battery, + side hooked up to the button, other side of the button
hooked to the resistor, hooked to the long lead of the LED, then back to
the - terminal of the battery through the short lead. LEDs need more
than 1.5V, so use a 9V battery. You can get terminals and cases for them
at electronics stores.

For a 9V battery, use a 1000 ohm resistor (sometimes they are sold as
1k, where the k means 1000).

Use what is called a "Normally Open" button, or N/O for short. That
means the terminals aren't connected until you push the button.

Now, when you push the button, the circuit will be completed, allowing
current to flow through the button to the resistor, thorough that, to
the LED, and back to the battery. This will light up the LED.

For two LEDs, just hook up another 1000 ohm resistor to the same button
terminal, then to the long lead of another LED. The short lead goes to
the - terminal of the battery. There should be no connection between the
long terminals of the LEDs; they should be independent strings of
components.

(view with fixed font, like courier)

1 LED:

+battery --- button --- resistor --- LED --- battery-

2 LEDs:

+ battery --- button --- resistor --- LED --- battery-
| |
'- resistor --- LED -'

The long lead of the LED should be on the left. If there isn't a long
lead, then there is occasionally a little flat spot in the epoxy case on
the - side.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.