# Homework Help: Short question about graphing AC voltage before rectificaiton

1. May 27, 2012

### Femme_physics

Last edited by a moderator: May 6, 2017
2. May 27, 2012

### I like Serena

Hmm, Vp to the ground isn't the negative pulse.
It's the positive pulse.

Perhaps you should try to solve the circuit for a couple of voltages.

3. May 27, 2012

### Staff: Mentor

I think RL (and not its end where you have written "K") should return to the rectifier junction where you have earth wrongly connected.

4. May 27, 2012

### Ouabache

I agree with Nascent about the peculiar wiring on this diagram.
FP you actually indicate a better wiring in your 1st post of an earlier question :)

5. May 27, 2012

### Femme_physics

Last edited by a moderator: May 6, 2017
6. May 28, 2012

### Ouabache

Hi FP
Your full wave bridge rectifier connections look much better.

VP would only be a negative voltage if your transformer secondary were $180^o$ out of phase (as in dot notation of following figure) However, when they don't explicitly use dot notation, we assume the secondary is in-phase (What does that mean? what ILS also alluded, VP-to-Gnd is the positive voltage).

I don't see where you are taking the pull-down voltage into consideration. Perhaps you could say in you calculations $$V_{A-G}(max)[\frac{N_ב}{N_א}]$$
http://i1131.photobucket.com/albums/m543/loxandbagels/scrcircuitwithpulldownxfmr.jpg [Broken]

Last edited by a moderator: May 6, 2017
7. May 28, 2012

### Femme_physics

From some reason I always thought that it's the other way around....

http://img838.imageshack.us/img838/9165/oppositenormal.jpg [Broken]

But you're my source, Quab, so I'll amend my err and instead of the dotted line for VP I'll add a full line indicating there's a voltage there, and at negative wave there isn't. Much appreciated

Last edited by a moderator: May 6, 2017
8. May 28, 2012

### Ouabache

if I made an error, I am sure someone will 'politely' supply correction.

So my username Ouabache is the French spelling of a native American word
for the river that runs alongside my university in northern Indiana. (etymology)

Last edited: May 28, 2012
9. May 28, 2012

### I like Serena

Regardless of the orientation, opposite or normal, Vp always has to be higher than the earth connection (0 V).

If Vp were lower than the earth connection, you'd have a short circuit.