DC output from a bridge rectifier.

[Rampage]

Been thinking about this. From standard UK 50Hz 230 Uo into a bridge rectifier the output would be 'b' on the drawing below?
Thanks.

 

[snowhead]

Might B, can you explain why tho'?

 

[telectrix]

i'll say b because 4 ------- are better than 2.

 

[Rampage]

Might B, can you explain why tho'?

I did realise it looked like breasts after I drew it!

 

[Knobhead]

Fig B. Peak voltage *1.41 RMS
Fig A is half wave

 

[tazz]

yes B looks right, if it any help capactitors are used after rectifiers to smoth out the ac, ie draw a line at the top of all the waves, will never be a true line but near to dc as you will get.
So for telectrix, treat as a half cut bra to hide the -------....lol

 

[Knobhead]

Tel's aways half cut View attachment 14594

 

[Rampage]

Might B, can you explain why tho'?

Because the negative half cycle rather than being removed is relocated into the positive half cycle.
Cant really think of how to describe it!

 

[Rampage]

Fig B. Peak voltage *1.41 RMS
Fig A is half wave

So would the output RMS voltage be higher than 230v?
Figure A would be achieved by using one diode on the Line and one on the Neutral?

Just something I was thinking about while driving earlier.

 

[Knobhead]

326V from 230V AC
RMS *√2

 

[tazz]

well electronic devices mess up patrical theories, the reason for the extra wave is after rectification the output is 100hz, most diodes have a loss of 0.4v - 0.5v so there is a loss
But with 100hz you do get more ------- for you money...!

 

[snowhead]

That's the basics mastered,, A.C to D.C.

Now think about P.W.M and you'll be able to explain how a V.S.D works.

 

[tazz]

I think VSD and 3 phase control is a bit over the top for a basic information post

 

[Rampage]

326V from 230V AC
RMS *√2

So that's where the 1.414 comes from! I never realised it's the square root of 2!
The inverse being 0.707

Still a bit confused though, is the RMS from the output of the bridge rectifier still 230v? Or does RMS not apply to DC? Meaning it could be called 325v rippled?

 

[tazz]

Wow ram were geting carried away rms relates to 3 phase, if you take Tonys post you will see rms would provide you with phase to phase votage

 

[Knobhead]

RMS applies to single phase as well

Phase to phase voltag is phase to neutral * √3

 

[tazz]

Tony you are totally correct, but i cant think of an example to explain

 

[Knobhead]

So that's where the 1.414 comes from! I never realised it's the square root of 2!
The inverse being 0.707

Still a bit confused though, is the RMS from the output of the bridge rectifier still 230v? Or does RMS not apply to DC? Meaning it could be called 325v rippled?

For full wave rectification the mean value is the RMS value, you will start to get near peak value if you start to introduce capacitors.
Somewhere I've got some drawings that may help. Somewhere being the operative word!

For three phase chuck RMS out of the window! It gets nearer to peak voltage.

 

[Knobhead]

Typical I've got three phase but not single.

View attachment 14597
3 phase full wave rectification. you can see the sharp change over from one diode to the next.

 

[Knobhead]

I'll do some singe phase drawings for you, but it won't be tonight.