PSN-L Email List Message

Subject: Re: The Magic
From: tchannel1@............
Date: Sat, 7 Jul 2007 17:52:53 -0600

```Hi Chris,  That is a good idea..........The visitors to the Museum are =
mostly tour groups of kids...They love to touch things, and maybe I =
could work something like this up.   I think that would explain the =
Magic very well.
Thanks, Ted
----- Original Message -----=20
From: ChrisAtUpw@..........
To: psn-l@.................
Sent: Saturday, July 07, 2007 4:53 PM
Subject: Re: The Magic

In a message dated 2007/07/07, tchannel1@............ writes:

She is often at the computer, by the Sensor, when people visit the =
museum.  One question she gets, is "How does it work"  She understands =
how it is built and all the parts, but when the questions focuses on the =
magnetic field and the coil, she can only discuss their interaction, =
creates a current, like "Magic"

Hi Ted,=20
=20
Movement of a coil in a magnetic changing field does not =
produce a current, but a voltage across the ends of the coil. This =
voltage is proportional to the number of turns, to the area of the coil =
and to the rate of change of the field.=20
A current flowing in a conductor has a ring magnetic field =
assocciated with it. If you use a circular solenoid, the turns add up to =
give an axial agnetic field.

I use a school demo system having quad NdFeB magnets on two =
parallel mild steel backplates. I use a relay coil on a handle connected =
to back to back red and green LEDs. You move the coil one way and the =
red LED lights, the other way and the green LED lights. If you move the =
coil more rapidly, the LEDs glow a lot brighter. Why not make up a =
similar model for the museum?

I have seen a formula explaining the three factors, The Field, The =
Coil, and The Velocity..........
Could someone tell me or direct me to an explanation of "The Magic"  =
which is really the basic for this type of sensor.

Regards,

Hi Chris,  That is a good =
idea..........The=20
visitors to the Museum are mostly tour groups of kids...They love to =
touch=20
things, and maybe I could work something like this up.   I =
think that=20
would explain the Magic very well.
Thanks, Ted

----- Original Message -----
From:=20
ChrisAtUpw@.......
To: psn-l@..............
Sent: Saturday, July 07, 2007 =
4:53=20
PM
Subject: Re: The Magic
In a=20
message dated 2007/07/07, tchannel1@............=20
writes:
She is often at the computer, by the Sensor, when people =
visit=20
the museum.  One question she gets, is "How does it work"  =
She=20
understands how it is built and all the parts, but when the =
questions=20
focuses on the magnetic field and the coil, she can only discuss =
their=20
interaction, creates a current, like "Magic"Hi Ted,=20
=20
Movement of a coil in a =
magnetic=20
changing field does not produce a current, but a voltage across the =
ends of=20
the coil. This voltage is proportional to the number of turns, to the =
area of=20
the coil and to the rate of change of the field.=20
A current flowing in a =
conductor has=20
a ring magnetic field assocciated with it. If you use a circular =
solenoid, the=20
turns add up to give an axial agnetic field.    =
I use a school demo system =
magnets on two parallel mild steel backplates. I use a relay coil on a =
handle=20
connected to back to back red and green LEDs. You move the coil one =
way and=20
the red LED lights, the other way and the green LED lights. If you =
move the=20
coil more rapidly, the LEDs glow a lot brighter. Why not make up a =
similar=20
model for the museum?
I have=20
seen a formula explaining the three factors, The Field, The Coil, =
and The=20
Velocity..........Could someone tell me or direct me to an =
explanation of "The=20
Magic"  which is really the basic for this type of=20
sensor.      =20
Regards,       Chris =
Chapman=20

```