Bridge Rectifier efficiency problem

[MarcL]

I am building a bridge rectifier using store bought components. I am using 5 X 35A 600V rectifiers.

What I am finding is that if rectifier 1 is producing 1V (hypothetically) and I then attach it to a bus, when I add the second rectifier, it doesn't double as one would expect.

The bus now produces 1.8V (hypothetically). As I increase the number of rectifiers, the voltage across the bus doesn't add as one might expect, such as 5 rectifiers at 1V should theoretically produce 5 V, but instead the efficiency is so poor that it produces less than 3V across the bus.

What is the fix? Is there one? Or is that just the way it is? Am I missing a basic principle in electronics that explains this away? etc...

 

[KMoffett]

Not sure how you are using the rectifiers. Can you post a schematic? The forward voltage drop of standard silicon rectifier is about 0.6V, not 1V. 3V for a series string of 5 rectifiers (0.6x5=3) is about right.

Ken

 

[MarcL]

I'm not talking about a voltage drop from the rectifier, but rather a voltage drop when I connect all the power derived from the rectifiers.

hence the hypothetical 1V used as just an random number.

To re-iterate 5 X 1V should get me 5V as opposed to the less than 3V I am now getting. Is there some kind of voltage loss due to resistance etc..... Do I need to connect a diode or MOSFET before I connect them to a bus.

Or am I still missing a basic principle in electronics?

 

[blueroomelectronics]

What are you trying to build? Most diodes are about 0.6V - 0.7V drop (varies with temperature and current too)

 

[KMoffett]

Again, can you explain what you really trying to do, and post a drawing, as your written explanation doesn't make it clear. Rectifies don't "produce" any voltage. What is the bus that you refered to?

Ken

 

[dknguyen]

PLease post a schematic because I don't see how bridge rectifier boosts voltage. THey only rectify.

Note that the DC-bias of the absolute value of a sine wave (a rectified sine wave) is sqrt(2) of the peak value. So if you smooth out a sine wave to get DC, the DC produced is less than the peak voltage of the sine input.