Circuit Lab B/C

UTF-8 U+6211 U+662F
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Re: Circuit Lab B/C

Post by UTF-8 U+6211 U+662F » February 24th, 2019, 9:03 am

Pastaman202 wrote:At one of my invites, there was a switch that connected with 2 terminals, and you are given a capacitor, battery, lamp and resistor. The question was to set up a schematic diagram of how when the switch is connected to one terminal, the light bulb starts dim and get brighter and brighter, while the other starts bright and gets dimmer and dimmer. Does anyone know how to set this up? P.S. this was a div B test. Thanks!
You'd have to set it up so that the capacitor discharges for the one switch position and recharges for the other switch position. So you'd have two RC circuits with a switch going in between them.

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Re: Circuit Lab B/C

Post by JavaScriptCoder » March 6th, 2019, 11:01 am

I've been looking at past practice tests after doing some research on circuit lab, and I saw a y-shaped load, with a resistance on each resistor. I can't really figure out what a y-delta transform is and how that's supposed to work, and I also don't really understand how the current is supposed to flow in the y. Can someone tell me:

a) this is an AC concept, will it be tested
b) if it is tested, how can I best understand it?

Thanks~!
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Re: Circuit Lab B/C

Post by UTF-8 U+6211 U+662F » March 6th, 2019, 11:33 am

JavaScriptCoder wrote:I've been looking at past practice tests after doing some research on circuit lab, and I saw a y-shaped load, with a resistance on each resistor. I can't really figure out what a y-delta transform is and how that's supposed to work, and I also don't really understand how the current is supposed to flow in the y. Can someone tell me:

a) this is an AC concept, will it be tested
b) if it is tested, how can I best understand it?

Thanks~!
Y-Delta transform is a way to simplify circuits. The two circuit pieces are equivalent and can exist in either DC or AC circuits. Current won't flow in the Y by itself: the purpose is the transform is to simplify a smaller piece in a larger and more complicated circuit. Check out this: https://www.khanacademy.org/science/ele ... r-networks
https://www.allaboutcircuits.com/textbo ... nversions/

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Re: Circuit Lab B/C

Post by JavaScriptCoder » March 6th, 2019, 1:29 pm

Thank you!
Here to help!~

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Re: Circuit Lab B/C

Post by jaggie34 » April 4th, 2019, 9:53 pm

Anyone think it would be useful looking into magnetic moment?
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and Circuit Lab too I guess

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Re: Circuit Lab B/C

Post by UTF-8 U+6211 U+662F » April 5th, 2019, 11:32 am

jaggie34 wrote:Anyone think it would be useful looking into magnetic moment?
Probably yes.

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Re: Circuit Lab B/C

Post by Boss » April 18th, 2019, 11:20 am

I know that the rules mention RC time constant questions, as well as capacitor questions, being permitted in division c. Would questions regarding other aspects beyond simple calculations of an RC time constant be permitted? I would think that if resistors and capacitors are permitted, then by extension, things like low-pass and high-pass filters would be allowed.

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Re: Circuit Lab B/C

Post by wec01 » April 18th, 2019, 1:37 pm

Boss wrote:I know that the rules mention RC time constant questions, as well as capacitor questions, being permitted in division c. Would questions regarding other aspects beyond simple calculations of an RC time constant be permitted? I would think that if resistors and capacitors are permitted, then by extension, things like low-pass and high-pass filters would be allowed.
I would say yes; generally if you think it would be allowed, some test writers will too.
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Re: Circuit Lab B/C

Post by neerja.shah » May 2nd, 2019, 5:04 pm

So just for anyone who might want to know what to expect on some tests here is list of things that you may see. I live in Ohio where the compititon is very hard, especially at State (considering that the national champs and runner up were from ohio). Anyways...here is the list:
- i always had a lab portion so become very good at identifying resistors in case they give you a huge pile
- a list of special symbols (sybols such as the ground symbol, switches, ect) put in your binder, just in case
- a list of inventors and when they invented things
- terms in SI units
that covers a huge part and might as well keep them in your binder just in case.............
hope this helps and good luck :)

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Re: Circuit Lab B/C

Post by lindsmaurer » May 4th, 2019, 10:28 am

Speaking of Ohio, the circuit lab test for div B had 5 different labs, 3 of which were done alongside the test and 2 of which were timed with each pair having 5 minutes total to complete both simultaneously. The test was also very very long, and very difficult. We only got about 3/4 to 4/5 of the way through and we still won.
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