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Re: Shock Value B/Circuit Lab C
Posted: March 11th, 2013, 10:34 pm
by PicturePerfect
One more question... For now.
What devices would we need to know how to use for Shock Value?
Re: Shock Value B/Circuit Lab C
Posted: March 12th, 2013, 5:46 am
by Skink
By devices you mean instruments? Multimeters (bring your own) and compasses? There's also supposedly something that finds the poles of a magnet quickly, but I've never used one myself.
Re: Shock Value B/Circuit Lab C
Posted: March 12th, 2013, 4:29 pm
by PicturePerfect
Okay, thanks! (And yes I mean instruments:) )
Re: Shock Value B/Circuit Lab C
Posted: March 12th, 2013, 5:18 pm
by UQOnyx
For Shock Value, IMO I recommend studying electromagnetism. If you got V=IR, and some circuit and other formulas, study electromagnetism. We got 4th place for States, and could have gotten 1st but we didn't know two electromagnetism questions and guessed those.
Re: Shock Value B/Circuit Lab C
Posted: March 12th, 2013, 5:31 pm
by Bozongle
UQOnyx wrote:For Shock Value, IMO I recommend studying electromagnetism. If you got V=IR, and some circuit and other formulas, study electromagnetism. We got 4th place for States, and could have gotten 1st but we didn't know two electromagnetism questions and guessed those.
Do you remember what those two questions were?
Re: Shock Value B/Circuit Lab C
Posted: March 14th, 2013, 6:11 pm
by -274degreesC
Why do we take the reciprocal of the sum of the reciprocals of parallel resistors? (What is the formula derived from?)
Re: Shock Value B/Circuit Lab C
Posted: March 14th, 2013, 6:43 pm
by Schrodingerscat
-274degreesC wrote:Why do we take the reciprocal of the sum of the reciprocals of parallel resistors? (What is the formula derived from?)
This website explains its derivation:
http://engineersphere.com/basic-electri ... rmula.html.
Re: Shock Value B/Circuit Lab C
Posted: March 14th, 2013, 6:47 pm
by Infinity Flat
-274degreesC wrote:Why do we take the reciprocal of the sum of the reciprocals of parallel resistors? (What is the formula derived from?)
The conductance equals one over the resistance.
In a parallel circuit the electrons have multiple paths to flow through, so the conductance of each path adds to give the total conductance.
C_T = C_1 + C_2 +...
When changed back to resistance yields
C_T = 1 / R_1 + 1 / R_2 +...
So the total equivalent resistance is then
R_T = 1 / C_T = 1 / (1 / R_1 + 1 / R_2 +...)
Re: Shock Value B/Circuit Lab C
Posted: March 14th, 2013, 6:48 pm
by Skink
Yes, what I've found is that deriving equations is much easier if you can work in terms of conductance. That's what my circuit math books all use, so doing so must be some sort of standard.
Re: Shock Value B/Circuit Lab C
Posted: March 16th, 2013, 10:56 am
by Unbihexium
It seems like people have trouble with circuit analysis concepts sometimes, and while I haven't seen much complex analysis at competition, I really suggest people try to learn Node Voltage analysis, it really makes things go faster in many cases. Also, just wondering, what Diode models do people prefer? the ideal mathematical model, or the shockley more realistic ideal model? Has anyone bumped into any really weird stuff on tests?