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From:	John <jjhudak AT gmail DOT com>
Subject:	Re: [geda-user] Daughter's Science Fair
Date:	Mon, 19 Mar 2012 09:26:13 -0400
To:	"geda-user AT delorie DOT com" <geda-user AT delorie DOT com>
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Reply-To:	geda-user AT delorie DOT com

Use a solid state relay or make your own with a 555 timer and a 2n3904 transistor as the base components with associated R's, C's and diodes



On Mar 16, 2012, at 4:59 PM, Vanessa Ezekowitz <vanessaezekowitz AT gmail DOT com> wrote:

> You guys are missing one of the fundamental ideas for this kind of project:  a chopper circuit.
> 
> Connect a few batteries, a switch, the coil of a low-voltage relay, and the "normally closed" switch in the relay in series with one of your coils (your primary) on the nail:
> 
> battery -> relay coil -> relay normally closed switch -
> -> your power switch -> your primary coil -> back to battery
> 
> Connect the other coil (your secondary) on the nail to your light bulb (or better, an LED).
> 
> When you close the switch, assuming the batteries add up to enough voltage, the relay will start cycling rapidly, "chopping up" the DC and inducing something not too different from an AC voltage in your primary coil.
> 
> That should, in turn, induce a voltage in your secondary and light your bulb/LED/whatever.
> 
> Yes, it'll wear the relay out after a while, but its not like this needs to last more than a couple of days anyway.
> 
> -- 
> "There are some things in life worth obsessing over.  Most
> things aren't, and when you learn that, life improves."
> http://digitalaudioconcepts.com
> Vanessa Ezekowitz <vanessaezekowitz AT gmail DOT com>
> 

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