AC Theory questions

[billynw]

Hi guys,
Just wanted to know if anyone could help me out with this one.

I doing day release, CG 2330 level 3 at the moment.

Does anyone know of any web sites that has any AC Theory question's on ?
So I can get some practise.

At the moment I'm doing some revision on Inductive/capacitive reactance & all that good stuff.

I'm not back in college till next week & wanted to do some questions.

If anyone could please help.

Many thanks

 

[andy]

not sure of sites, but your lecturer should be givin you loads of exam papers before your exam. i take it as you have it in the next few weeks?

 

[billynw]

Thanks for your help mate.

Yea I will have a chat with him next week.
I just thought I would get abit more in.


My exams are in June,
Thanks again

 

[Adam_151]

Try something I just made up on the spot

I have a 5v 20ma LED and a 240V AC 50hz power source, I have a full wave recifier and a capacititor so I can run my LED, what value is the capacitor?

 

[andy]

Try something I just made up on the spot

I have a 5v 20ma LED and a 240V AC 50hz power source, I have a full wave recifier and a capacititor so I can run my LED, what value is the capacitor?

nowt like that is on the 2330... or my lecturer has missed some out....

 

[Jim2287]

Try something I just made up on the spot

I have a 5v 20ma LED and a 240V AC 50hz power source, I have a full wave recifier and a capacititor so I can run my LED, what value is the capacitor?

out of interest is it 0.000016 ?

or 0.000083 ?

 

[lizzieg]

Billy
Isn't this the 1st year for 2330 level 3?. I'm doing level 1 and 2 at the moment and understood it was only the second year.
Our college hasn't been too helpful on exam questions, cos as they are done on line they reckon they don't know what is being asked......not sure weather to believe them or not....

 

[Adam_151]

Try something I just made up on the spot

I have a 5v 20ma LED and a 240V AC 50hz power source, I have a full wave recifier and a capacititor so I can run my LED, what value is the capacitor?

out of interest is it 0.000016 ?

or 0.000083

What units? anyway its wrong

 

[Jim2287]

farads, was just a little attempt

equation ?

 

[andy]

Billy
Isn't this the 1st year for 2330 level 3?. I'm doing level 1 and 2 at the moment and understood it was only the second year.
Our college hasn't been too helpful on exam questions, cos as they are done on line they reckon they don't know what is being asked......not sure weather to believe them or not....

im on the same course. we do the exams online, but our lecturer gets us loads of questions. he doesnt know 100% whats on the exam, but in the last 2 he has covered everything thats on the exam in test papers

 

[Adam_151]

farads, was just a little attempt

equation ?

reactance = 1 / (2 * pi * f * C)

reactance is in ohms, frequency(F) is in hz, and capacitor value (C) in farads

 

[Jim2287]

oh right yeah, never applied it to electronics, thanks


i did :

Smoothing capacitor for 10% ripple,

C = ( 5 × Io ) / ( Vs × f )

C = smoothing capacitance in farads (F)
Io = output current from the supply in amps (A)
Vs = supply voltage in volts (V)
f = frequency of the AC supply in hertz (Hz)

 

[billynw]

Thanks for all the help here guys.

I'm doing the 2330 Level 3.

This is the second & final year.

The 2330 Level 1 + level 2 are now combined into one year.
The 2330 Level 3 is the second & final year
I'm also doing the NVQ 3 along side this

This course is done 1 day a week, 12 hours a day (long day I know)

I'm sure the 2330 level 1 & 2, is the old 2360 part 1
& the 2320 Level 3 is the old 2360 part 2.


I'm also sure that this is the first year C & G have ran the 2330 L3 course.
Last year I did the 2330 L2, that was also the first year, we did 4 online exams.

Confusing I know.....

BTW, I'm 29. Never to old to learn. right ?

 

[Adam_151]

Oh, I wasn't thinking of a capacitor to smoove it, its only a quick in dirty supply for an LED thats far than elegant , I was getting at using the capacitor as the voltage dropping element

 

[Spark123]

Try this one,
A coil of wire has a resistance of 8ohms and an inductance of 0.04h. It is connected to a supply of 100v at 50hz. Calculate the current which flows.