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#67665 - 07/11/06 07:44 PM Mind bender
Bill39 Offline
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Registered: 11/28/01
Posts: 75
Loc: Indianapolis, IN, USA
Here's one my son brought home from school and so far he's got me stumped:

Create a circuit in which initially, four lamps are ON while the fifth lamp is OFF. Also, you must be able to unscrew one of the four burning lamps in order to turn on the fifth lamp. You are not allowed to change any of the wiring to get this to work.

Darn College-boy!!
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#67666 - 07/11/06 08:24 PM Re: Mind bender
gfretwell Offline


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Registered: 07/20/04
Posts: 9036
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What kind of parts can I use?
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#67667 - 07/11/06 08:29 PM Re: Mind bender
Bill39 Offline
Member
Registered: 11/28/01
Posts: 75
Loc: Indianapolis, IN, USA
A battery, the lamps, (& holders) & any # of wires you need.

That's it, no switches, etc. A simple circuit connected in any combination of series or parallel.
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#67668 - 07/11/06 08:31 PM Re: Mind bender
e57 Offline
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Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
Thyristor, zenor diode and SCR to control a relay? Multiples of each could do it arranged correctly, oh a few resistors too. Also what is the voltage and current?

You posted while I was pondering...

[This message has been edited by e57 (edited 07-11-2006).]
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Mark Heller
"Well - I oughta....." -Jackie Gleason
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#67669 - 07/11/06 08:32 PM Re: Mind bender
e57 Offline
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Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
Hmmm, not legal to install? But operational?

[This message has been edited by e57 (edited 07-11-2006).]
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Mark Heller
"Well - I oughta....." -Jackie Gleason
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#67670 - 07/11/06 08:37 PM Re: Mind bender
gfretwell Offline


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Registered: 07/20/04
Posts: 9036
Loc: Estero,Fl,usa
Are all of the light bulbs the same wattage?
If the 5th one was a small fraction of the others and in parallel with the one you unscrew it would work.
It sounds like one of those "all american five" radio filiment deals.
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#67671 - 07/11/06 08:39 PM Re: Mind bender
e57 Offline
Member
Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
Voltage and lamp wattage?

You guys got me again in the two minute delay of my slow typing...

[This message has been edited by e57 (edited 07-11-2006).]
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Mark Heller
"Well - I oughta....." -Jackie Gleason
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#67672 - 07/11/06 08:42 PM Re: Mind bender
e57 Offline
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Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
Thats what I was thinking too.
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Mark Heller
"Well - I oughta....." -Jackie Gleason
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#67673 - 07/11/06 08:46 PM Re: Mind bender
Bill39 Offline
Member
Registered: 11/28/01
Posts: 75
Loc: Indianapolis, IN, USA
Guys,
This is a college physics lab question.
No NEC code or inspectors to worry about.

Wattage of lamps was not given. The info in my original post is all the info the prof gave them.
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#67674 - 07/11/06 09:16 PM Re: Mind bender
LarryC Offline
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Registered: 07/05/04
Posts: 780
Loc: Winchester, NH, US
Hint: Brooklyn

LarryC
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