How does a centre tap transformer enable full wave rectification?

[PainterGuy]

Seriously I don't know.

Jiggy-Ninja told me that if you have windings wounded in the same directions then the currents in the primary and secondary are in phase. That's what I know.

So to keep things simple and understandable for me I assumed they are in phase.

Is that diagram correct? Tell me please.

Cheers

 

[sophiecentaur]

I think he meant that the phases of the two Secondaries are equal - so the voltages add up.
That diagram has an error in it. There is a connection across one of the secondary windings. That is a short circuit. You need to erase the line coming from the centre tap. The secondary is now a single winding of twice the number of turns.
I don't understand why you don't just look at a link about simple transformer theory. Did you ever google it?

 

[I_am_learning]

Hello once again everyone,

Just a small question I hope you would not mind its asking.

I will use Jiggy-Ninja's diagram for my question. As the CTT splits the voltage into 120V around the two secondaries, so I was thinking if it is possible to get some 240V some way. I think this is not possible. By combining the voltage one can get 'overall' increased current as is the case with combining two batteries in parallel.

Have a see here on this link please:-
http://img97.imageshack.us/img97/9539/ctt1.jpg

"B" in the diagram is a bulb and both batteries of 120V connected in parallel.

Is my understanding correct? Tell me please.

Cheers

With that drawing you would explode the transformer.
Actually, the drawing (both Ninja's and Yours) is quite misleading for beginers. The top side voltage should be written as +120, Central as 0 and Bottom side as -120. That should make it clear, that you shouln't join the top side and bottom side, it would be like placing two batteris End to end (i.e. in series) and then short circuiting their the end terminals.

(Yeah, you can get + and - voltage in AC also. That occurs when two voltages are perfectly 180 out of phase.)

 

[Evil Bunny]

Why should you expect the primary and secondary currents to be in phase? That's a huge assumption.

Because they are. He is exactly correct. Those arrows on the secondary will be pointing in the same direction (Now, they may or may not be pointing the same way as the primary) but they will absolutely be pointing in the same direction. In phase!

EDIT: I just read it again. I think you are saying the same as me. The primary and secondary currents might not be flowing in the same direction... my point was that If the arrow is pointing up from L2 to neutral it will also be pointing up from neutral to L1 at the same time. I think you're saying the same thing. My apologies.

 

[sophiecentaur]

I was just going to get shirty with you. Then I read the second half. Ha ha.

 

[grunfunke]

I tried to find the option to start a new thread, but I found it nowhere. Anyways, I have two very basic questions regarding center tapped transformer.

1:See this first:http://sdrv.ms/RmHXQV
How does the sine wave of the voltage reverses for the upper and lower half of center tapped transformer?
To explain my question further, at time 0 the sine wave is at the reference line for both parts of the secondary winding. As time passes it is going in positive direction for the top half, and going negative direction in the bottom half. This reversing of the waves enables us to get full wave rectification. But how does the reversing occurs?

2:See this first:http://sdrv.ms/RmHXjH
I don't understand why the current is emerging from the ground. Can you please explain this?