# ETO Online Quiz Sheets.

Discussion in 'Site Issues & Feedback' started by ericgibbs, Feb 19, 2012.

1. ### MrAlWell-Known MemberMost Helpful Member

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Hi,

Yes i wanted to make the questions a little bit interesting and hopefully get some people to look at some more electronic/electrical theory.

There's a problem in question 4 however, the resistor value somehow got left out. The question starts:
"Q4: The formula for the 3db cutoff frequency of a low pass filter made from a resistor R in series with a capacitor C and driven by an AC voltage source and taking the output from the junction of the resistor and capacitor to ground is: F=1/(2*pi*R*C)
Find the capacitor value that causes a 3db cut in the gain at a frequency F of 1 kHz. Approximate the capacitor value to three significant decimal places."

"Q4: The formula for the 3db cutoff frequency of a low pass filter made from a resistor R in series with a capacitor C and driven by an AC voltage source and taking the output from the junction of the resistor and capacitor to ground is: F=1/(2*pi*R*C)
Using a resistor value of 1k, find the capacitor value that causes a 3db cut in the gain at a frequency F of 1 kHz. Approximate the capacitor value to three significant decimal places."

We'll have to wait for Eric to fix it. Thanks to pommie for catching that so quickly. If anyone spots anything else like that please let me know.

Last edited: Feb 25, 2012
2. ### ericgibbsWell-Known MemberMost Helpful Member

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hi Al,
Your corrected text Q4, has been updated, let me know if there is a problem

3. ### MrAlWell-Known MemberMost Helpful Member

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Hi,

Thanks Eric.

Did something go wrong with Quiz V3 though or is it my browser?
There is no 'equations' for Q1 for example, and the answers to many of the questions dont make sense except for maybe the right answer. I could have sworn it was ok yesterday.

Last edited: Feb 25, 2012

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5. ### ericgibbsWell-Known MemberMost Helpful Member

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hi Al,
All I do is Copy and Paste from your text.

I will check Quiz3 later, let you know

EDIT:
QuizV3 seems to have gone crazy.?? its not been changed by me since it was installed. I will check and try to find what is causing the problem.

EDIT2:
Re-uploaded the QuizV3, looks OK now. No explanation to why it was corrupted from yesterday.??

Last edited: Feb 25, 2012
6. ### MrAlWell-Known MemberMost Helpful Member

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Hi Eric,

OH sure i am not blaming you for any typos or anything like that, any typos are certainly all my fault as well as emissions or whatever. What i didnt know beforehand was that you would copy and paste (although i should have figured that) so some lines may have unusual terminations/line feeds which need to be corrected, again all my fault

Thanks to the other members for looking this stuff over so we can find errors and correct them, and i hope you all find these questions interesting.

7. ### ericgibbsWell-Known MemberMost Helpful Member

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hi Al,
Its not a problem for me to edit the quizzes as required to correct for typo's etc, please feel free to PM me if required, with any corrections.

E.

8. ### meowth08Member

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Hi,

I'm always visiting here hoping to see more online quizzes. They are very interesting. Although I only got 2 on Mr Al's quiz, I'm still craving for more.

I am hoping that "collin", would soon give his very interesting and tricky quiz. It's would be a very good experience to take a quiz made by someone who has experience in teaching electronics for more than 30 years. He also has made "clever circuits" as he describe them.

Well, this is just a kind request from a newbie here in ETO.

Last edited: Feb 26, 2012
9. ### ericgibbsWell-Known MemberMost Helpful Member

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Last edited: Feb 27, 2012
10. ### PommieWell-Known MemberMost Helpful Member

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OK, why is the first answer not 12A 110V? Plus, I'm not sure about a laser printer. Wiki states that it uses dry ink which is then melted and so 2 of the answers could be correct.

And, I had no idea on knob and tube, is that an American thing?

Mike.

11. ### DerStrom8Super ModeratorMost Helpful Member

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Got a 9 on that one (which is surprising ). I agree with Mike--laser printers use toner, which is dried powder ink, and the laser melts it onto the paper.

Mike, to my knowledge, knob and tube is found all over the world. I don't want to say any more, so as not to give anything away.

Nice quiz 3v0. Thanks

Regards

12. ### Nigel GoodwinSuper ModeratorMost Helpful Member

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Because you don't want a fuse that has such a low voltage rating.

I thought toner was fine plastic granules?.

I would suggest so, and pretty primitive too

13. ### PommieWell-Known MemberMost Helpful Member

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If it's rated for 110V then it will work at that voltage. Why over spec something?

Edit, I've never understood voltage ratings on fuses anyway. A 20mm fuse should have a voltage rating based on it's size.

Mike.

Last edited: Feb 27, 2012
14. ### ericgibbsWell-Known MemberMost Helpful Member

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hi.
The QuizV8 is having a problem showing the Images for the questions, hope to have that fixed soon.

E.

15. ### Nigel GoodwinSuper ModeratorMost Helpful Member

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The voltage rating is how much voltage it can 'break' - if a fuse was only rated at 110V then a higher voltage isn't guaranteed to be stopped when the fuse blows.

So assuming it's 110V, and you accidentally plug it in 220V mains - the fuse may well blow (because of the extra current drawn) - but current may well still flow as the fuse isn't rated to stop 220V arcing across it.

It's essential to ensure that fuses are correctly rated.

16. ### ericgibbsWell-Known MemberMost Helpful Member

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Last edited: Feb 28, 2012
17. ### DerStrom8Super ModeratorMost Helpful Member

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I just noticed an error in my own. On Q2, I wrote the question as

However, "common resistor values" differ depending on the tolerance, so I should have specified ±10%. Thanks

18. ### PommieWell-Known MemberMost Helpful Member

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On Q4, don't we need to know the operating voltage?

Mike.

19. ### DerStrom8Super ModeratorMost Helpful Member

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If you're referring to mine, no. It's only asking for the total resistance. I.E. if you connected an ohmmeter directly between those points, what resistance would the meter read?

20. ### PommieWell-Known MemberMost Helpful Member

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But I've got 8V in and 25mA but don't know what is going out. Maybe the beer has fuddled my brain.

Mike.

21. ### DerStrom8Super ModeratorMost Helpful Member

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Hmm, I just realized that some of the questions are swapped around. Q4 is all the way down where Q10 should be, and Q10 is where Q4 should be...

So are you referring to Q10 then?

EDIT: Apparently it's only the "Q10 Marking" and "Q4 Marking" that's out of place.....

Anyway, 8 volts through two series resistors, and the total current it 25mA. That should be enough.

Last edited: Feb 28, 2012