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#152923 03/05/06 07:38 PM
Joined: Feb 2003
Posts: 368
M
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I vaguely remember seeing something like this in my grade 7 or 8 shop class in the early 1970's. If I am not mistaken though ours were powered by a big lamp battery instead of electricity.

Our instructor used it as a visual thing to show what the textbook was talking about.

Things like parallel and series circuits and three way switches. He always picked somebody to come up and wire it at the end of class.

#152924 03/06/06 11:52 AM
Joined: Aug 2001
Posts: 7,520
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Quote
I don't. In the era that this device would have been found in use, both adults and kids had more common sense and maturity.

I agree entirely. If it were being marketed to 6-year-olds to play with alone, then there might be cause for concern, and a harmless battery-powered version would be far more appropriate. But items such as this (and the resonance demonstrator in the other thread) were clearly designed and build for class demonstrations where there would have been suitable supervision.

It seems to me that these would have been set up on a bench and the class gathered round to watch the demonstration. In fact we did just such experiments when I was in school in the 1970s, both physics and chemistry.

If we're going to insist that the equipment is completely covered and idiot-proof, then we'd better not let chemistry students handle bottles of hydrochloric acid. Better not let the girls handle hot cake trays in cookery classes either (if they even do cookery these days!).

#152925 05/03/06 11:56 PM
Joined: Aug 2005
Posts: 24
G
Member
Remember prior to the 1970s we had an entirely different legal system. If you were a student and were stupid enough to touch a live circuit board like that not only did you get a good shock but also a smack in the back of the head by the teacher for being an idiot!

Let's see how that would be today.

We would sue the school district, the manufacture of every part on the project.
including personally the board members of those companies. The teacher would be fired. The school principal would have to resign along with the disrict superintendent due to media pressure. Electricity would be banned as a science topic.

Did I miss anything?

[This message has been edited by Gus99 (edited 05-03-2006).]

#152926 10/19/06 05:12 PM
Joined: Oct 2002
Posts: 482
Z
Member
Could it be an elementry level logic device?

#152927 10/21/06 04:15 AM
Joined: Jul 2002
Posts: 8,443
Likes: 3
Trumpy Offline OP
Member
This from n1ist:

Quote
Yes, it looks like a series/parallel demo.


Here's the schematic:

[Linked Image]

I'm not sure why the 4 bulbs are all in parallel without individual
switches; that would have made it more useful. Maybe it did double as a load bank.

#152928 10/21/06 06:14 AM
Joined: Aug 2001
Posts: 7,520
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Quote
I'm not sure why the 4 bulbs are all in parallel without individual switches;

Maybe the designer wanted a fair-sized fixed main load in comparison to the bulbs which can be switched into the circuit in series and just hardwiring four lamps together meant that all bulbs could be the same wattage for simplicity.

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