1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

ETO Online Quiz Sheets.

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

  1. MrAl

    MrAl Well-Known Member Most Helpful Member

    Joined:
    Sep 7, 2008
    Messages:
    11,029
    Likes:
    951
    Location:
    NJ
    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."

    It should read:
    "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. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,187
    Likes:
    644
    Location:
    Ex Yorks' Hants UK
    hi Al,
    Your corrected text Q4, has been updated, let me know if there is a problem
     
  3. MrAl

    MrAl Well-Known Member Most Helpful Member

    Joined:
    Sep 7, 2008
    Messages:
    11,029
    Likes:
    951
    Location:
    NJ
    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
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,187
    Likes:
    644
    Location:
    Ex Yorks' Hants UK

    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. MrAl

    MrAl Well-Known Member Most Helpful Member

    Joined:
    Sep 7, 2008
    Messages:
    11,029
    Likes:
    951
    Location:
    NJ
    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. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,187
    Likes:
    644
    Location:
    Ex Yorks' Hants UK
    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. meowth08

    meowth08 Member

    Joined:
    Aug 18, 2011
    Messages:
    241
    Likes:
    7
    Location:
    Philippines
    Hi,

    I'm always visiting here hoping to see more online quizzes. They are very interesting. Although I only got 2 :p 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. :D
     
    Last edited: Feb 26, 2012
  9. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,187
    Likes:
    644
    Location:
    Ex Yorks' Hants UK
    Last edited: Feb 27, 2012
  10. Pommie

    Pommie Well-Known Member Most Helpful Member

    Joined:
    Mar 18, 2005
    Messages:
    10,019
    Likes:
    317
    Location:
    Brisbane Australia
    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. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

    Joined:
    Aug 9, 2010
    Messages:
    5,484
    Likes:
    503
    Location:
    Vermont (GMT-5:00)
    Got a 9 on that one (which is surprising :D). 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 Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

    Joined:
    Nov 17, 2003
    Messages:
    39,227
    Likes:
    641
    Location:
    Derbyshire, UK
    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 :D
     
  13. Pommie

    Pommie Well-Known Member Most Helpful Member

    Joined:
    Mar 18, 2005
    Messages:
    10,019
    Likes:
    317
    Location:
    Brisbane Australia
    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. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,187
    Likes:
    644
    Location:
    Ex Yorks' Hants UK
    hi.
    The QuizV8 is having a problem showing the Images for the questions, hope to have that fixed soon.

    E.
     
  15. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

    Joined:
    Nov 17, 2003
    Messages:
    39,227
    Likes:
    641
    Location:
    Derbyshire, UK
    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. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,187
    Likes:
    644
    Location:
    Ex Yorks' Hants UK
    Last edited: Feb 28, 2012
  17. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

    Joined:
    Aug 9, 2010
    Messages:
    5,484
    Likes:
    503
    Location:
    Vermont (GMT-5:00)
    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. Pommie

    Pommie Well-Known Member Most Helpful Member

    Joined:
    Mar 18, 2005
    Messages:
    10,019
    Likes:
    317
    Location:
    Brisbane Australia
    On Q4, don't we need to know the operating voltage?

    Mike.
     
  19. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

    Joined:
    Aug 9, 2010
    Messages:
    5,484
    Likes:
    503
    Location:
    Vermont (GMT-5:00)
    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. Pommie

    Pommie Well-Known Member Most Helpful Member

    Joined:
    Mar 18, 2005
    Messages:
    10,019
    Likes:
    317
    Location:
    Brisbane Australia
    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. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

    Joined:
    Aug 9, 2010
    Messages:
    5,484
    Likes:
    503
    Location:
    Vermont (GMT-5:00)
    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

Share This Page