Mail Archives: geda-user/2012/03/16/14:54:30
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I can't comment on the resistor because I am at work and don't have time to
fully understand your circuit details. i would like to add some comments.
You may wish to show the students how they can see the invisable magnetic
field by putting some iron filings into a jar of glycerine. When you move
the jar close to the nail, the metal filings will arrange themselves in the
pattern of the magnetic field. You can accomplish the same thing, sort
of, by putting flat cardboard around the nail, and sprinkle the filings on
the cardboard - this is a little tricky because if the filings are too
close to the nail they will be sucked into it.
You could also get a galvenometer (or make one - web search) to show the
magnetic field...a compass would also work
John
On Fri, Mar 16, 2012 at 1:58 PM, GENE GLICK <geneglick AT optonline DOT net> wrote:
>
>
>
> On Fri, Mar 16, 2012 at 11:33 AM, Rob Butts wrote:
>
> So if I use a 1 watt 15k ohm resistor in series with the nail and an ac
> outlet that will give me 8ma alternating current and that should light the
> bulb?
>
> I don't think UL would approve :) Also, you don't want to endanger the
> kids. But - if you energize one coil with a DC source, then *move* the
> other coil around, you should get something to happen. Maybe a light bulb,
> or maybe a current meter would show the affect. In fact, if you have time
> to build a little turntable, somehow allowing the kids to spin the second
> coil - that should also work. Faster spins = brighter lights, or higher
> current readings - make a game out of it :)
>
> gene
>
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I can't comment on the resistor because I am at work and don't have=
time to fully understand your circuit details.=A0 i would like to add some=
comments.<br><br>You may wish to show the students how they can see the in=
visable magnetic field by putting some iron filings into a jar of glycerine=
.=A0 When you move the jar close to the nail, the metal filings will arrang=
e themselves in the pattern of the magnetic field.=A0=A0 You can accomplish=
the same thing, sort of, by putting flat=A0 cardboard around the nail, and=
sprinkle the filings on the cardboard - this is a little tricky because if=
the filings are too close to the nail they will be sucked into it.<br>
<br>You could also get a galvenometer (or make one - web search) to show th=
e magnetic field...a compass would also work<br><br>John<br><br><br><div cl=
ass=3D"gmail_quote">On Fri, Mar 16, 2012 at 1:58 PM, GENE GLICK <span dir=
=3D"ltr"><<a href=3D"mailto:geneglick AT optonline DOT net">geneglick AT optonline=
.net</a>></span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div class=3D"im"><div align=3D"LEFT"><font =
color=3D"#000000" face=3D"Verdana">=A0</font></div><font color=3D"#000000" =
face=3D"Verdana"><br>
</font><font color=3D"#000000" face=3D"Verdana"><br></font><div align=3D"LE=
FT"><font color=3D"#000000" face=3D"Verdana">On Fri, Mar 16, 2012 at 11:33 =
AM, Rob Butts wrote:</font></div><font color=3D"#000000" face=3D"Verdana"><=
br></font><div align=3D"LEFT">
<font color=3D"#000000" face=3D"Verdana">=A0<font size=3D"3">So if I use a =
1 watt 15k ohm resistor in series with the nail and an ac outlet that will =
give me 8ma alternating current and that should light the bulb? </font></fo=
nt></div>
<font color=3D"#000000" face=3D"Verdana" size=3D"3"><br></font></div><div a=
lign=3D"LEFT"><font color=3D"#000000" face=3D"Verdana" size=3D"3">I don'=
;t think UL would approve :) Also, you don't want to endanger the kids.=
=A0 But - if you energize one coil with a DC source, then *move* the other =
coil around, you should get something to happen.=A0 Maybe a light bulb, or =
maybe a current meter would show the affect.=A0 In fact, if you have time t=
o build a little turntable, somehow allowing the kids to spin the second co=
il - that should also work.=A0 Faster spins =3D brighter lights, or higher =
current readings - make a game out of it :)</font></div>
<span class=3D"HOEnZb"><font color=3D"#888888"><font color=3D"#000000" face=
=3D"Verdana" size=3D"3"><br></font><div align=3D"LEFT"><font color=3D"#0000=
00" face=3D"Verdana" size=3D"3">gene</font></div></font></span></blockquote=
></div><br>
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