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Standard Licence
Posted: Tue Feb 10, 2009 10:40 pm
by Zebedee
OK so there's a thread for people thinking of or having done a Foundation course, and now it's time for a thread for people considering or doing a Standard level course.
Tonight, the Ham College Standard class of 2009 commenced. Eight students have started the course - two of them WARSUG members
First up was some brain-bending regs and maths. What a way to start, on a very warm night
Re: Standard Licence
Posted: Tue Mar 03, 2009 6:29 pm
by robbage
OK here's a couple of questions in an exam for someone to answer for me
Question 3.1415926
The bias used in this amplifier circuit is
A) fixed bias
B) grid leak bias
C) cathode bias
D) combination bias
Question X
Which of the following statements is incorrect in relation to a full wave bridge rectifier circuit
A) It's transformer does not require a centre tap
B) The circuit requires two diodes
C) All diodes conduct at the same time
D) The output ripple frequency is 100 Hz
Re: Standard Licence
Posted: Tue Mar 03, 2009 6:49 pm
by Nick
No circuits to go with the questions
Re: Standard Licence
Posted: Tue Mar 03, 2009 10:24 pm
by Zebedee
Errrrrrrrrr
We're up to resistors in series and parallel
Re: Standard Licence
Posted: Tue Mar 03, 2009 10:37 pm
by meg
Zebedee wrote:We're up to resistors in series and parallel
And frankly my head is hurting already!
Re: Standard Licence
Posted: Tue Mar 03, 2009 10:45 pm
by VK6ZMS
robbage wrote:OK here's a couple of questions in an exam for someone to answer for me
Which of the following statements is incorrect in relation to a full wave bridge rectifier circuit
A) It's transformer does not require a centre tap
B) The circuit requires two diodes
C) All diodes conduct at the same time
D) The output ripple frequency is 100 Hz
A bridge rectifier requires 4 diodes.
Re: Standard Licence
Posted: Tue Mar 03, 2009 11:01 pm
by Tyranus
ooo I haven't done resistors in series or parallel for ages...well since I left school...
Re: Standard Licence
Posted: Wed Mar 04, 2009 5:11 am
by robbage
Nick wrote:No circuits to go with the questions
Yeah, that's how the question was presented to me
VK6ZMS wrote:A bridge rectifier requires 4 diodes.
That's what I thought too.. also only two diodes conduct at any point in time, no?
Re: Standard Licence
Posted: Wed Mar 04, 2009 5:38 am
by Nick
You can attain full wave rectification with two diodes and a centre tapped transformer as well
Re: Standard Licence
Posted: Wed Mar 04, 2009 8:42 am
by Zebedee
Nick wrote:You can attain full wave rectification with two diodes and a centre tapped transformer as well
True - but the question specifically referred to a bridge rectifier, which makes a centre-tapped transformer no good - as far as I understand it anyway.
Had the question said "which of the following is
correct" then answer A would be the one they are looking for I believe... As B is false - a bridge rectifier uses four diodes. C is false, as only two diodes conduct at any one time. And D is false, as the ripple frequency would be twice the input frequency, not always 100Hz.
So, I'd say that it was a misprint in the question, that's my best guess.
Re: Standard Licence
Posted: Wed Mar 04, 2009 1:48 pm
by Nick
Correct. It is all about taking the time to read not flick through the questions like I did.The first question needs a schematic to refer to to give an answer to.
Re: Standard Licence
Posted: Wed Mar 04, 2009 3:28 pm
by robbage
It might be a bug in the website where the questions were. All I know is I need to do a lot more reading on transmitters and receivers. And propagation.
Re: Standard Licence
Posted: Wed Mar 04, 2009 3:58 pm
by Zebedee
robbage wrote:All I know is I need to do a lot more reading on transmitters and receivers. And propagation.
Oh???
What are we up to?
Re: Standard Licence
Posted: Wed Mar 04, 2009 5:48 pm
by Nick
For propogation (HF) try here:
http://www.ips.gov.au/HF_Systems.
It has a host of information and can be useful also if you wish to find info like what frequency to use at a particular time to travel any distance world wide...
Re: Standard Licence
Posted: Thu Mar 05, 2009 5:24 am
by robbage
Zebedee wrote:robbage wrote:All I know is I need to do a lot more reading on transmitters and receivers. And propagation.
Oh???
What are we up to?
I booked in for the exam in late March
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