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Forums
4hv.org :: Forums :: General Science and Electronics
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Electrical Quizzes - QUIZ 8 POSTED

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Move Thread LAN_403
Dr. Dark Current
Sun Feb 19 2006, 08:10AM
Dr. Dark Current Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Part Scavenger wrote ...

How's about this? cheesey

When you push the button, voltage is no longer dropped across L1 and you can adjust R2 to whatever you want to modify it's brightness. You could also add a resistor above R1 if you care about the volt drop being the same.

Bulb 2 would never really turn off. (I think there was already posted schematic w/ the same prob.)
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Part Scavenger
Sun Feb 19 2006, 04:35PM
Part Scavenger Registered Member #79 Joined: Thu Feb 09 2006, 11:35AM
Location: Arkansas
Posts: 673
 		Oh, darn. That's true.
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HV Enthusiast
Sun Feb 19 2006, 08:32PM
HV Enthusiast Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
 		HINTS:

1. Use a 24VDC Source
2. Only components are 4 resistors, and the switch, and two bulbs
3. The design can be made so that each bulb illuminates the same when they are illuminated
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Thingmaker3
Sun Feb 19 2006, 09:21PM
Thingmaker3 Registered Member #124 Joined: Fri Feb 10 2006, 01:30PM
Location: Portland Oregon
Posts: 35
 		I would never have guessed this if I had not read that other thread this afternoon... the one with the whetstone bridge...
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Dr. Dark Current
Sun Feb 19 2006, 10:02PM
Dr. Dark Current Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
 		I have another one (the resistor values are just guessed, but should be close)

Right now I don't have time to examine Thingmaker's circuit, but something says me that it wont work properly... confused


1140386527 152 FT1067 Q5
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HV Enthusiast
Mon Feb 20 2006, 12:56AM
HV Enthusiast Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
 		Congratulations both Thingmaker and Jmartis. Both appear from quick look to be working solutions, although Thingmaker gets the cookie for posting a solution first . . . smile

Here is the next quiz . . .

QUIZ #4 - This should be a good one for those who like math . . .

What is the equivalent resistance of this infinite network if all resistors are equal???


1140396996 15 FT1067 Quiz04
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Nik
Mon Feb 20 2006, 01:39AM
Nik Registered Member #53 Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638
 		Fie, I am VERY close to haing an anwer for you but I have to find my grade 12 math notes to change it into something acceptable. Good problem, its deceptively simple.
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Electroholic
Mon Feb 20 2006, 06:37AM
Electroholic Registered Member #191 Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720
 		ha, i drew up the math on a paper, and i think i know what that is....i believe thats called the golden ratio
same as the ratio of a perfect 5 point star...
1.618033......
the second most beautiful number....
sorry for the OT...lol cheesey

yea so you multiply the R you use by 1.618...

oh just remember, it also equal 2*cos(78)+1
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HV Enthusiast
Mon Feb 20 2006, 01:01PM
HV Enthusiast Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
 		Congratulations JimmyJo. You got the correct answer.

Req = ((1+SQRT(5))/2) * R
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Marko
Mon Feb 20 2006, 03:57PM
Marko Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
 		Lol I forgot about the quiz...
Wanted to calculate for wheatstone bridge but guys already did it smile
..can I post a 'quiz' found something interesting rolleyes ?
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