This is obviously an ignorant question, but I can’t seem to find the answer.
I’ve made a few simple full bridge rectifiers from four single diodes/2-pin and having the voltage multiply by about 1.4x. These are mostly being used in single rail regulated power supplies.
Here I’ve grabbed a PCB for a common cathode dual anode full bridge rectifier to feed a single rail power supply and am getting no voltage increase at all, just the forward voltage drop. Not expected, and won’t give me the needed voltage from this transformer!
Is this how it’s supposed to work without any voltage increase across the full bridge rectifier?
I’ve made a few simple full bridge rectifiers from four single diodes/2-pin and having the voltage multiply by about 1.4x. These are mostly being used in single rail regulated power supplies.
Here I’ve grabbed a PCB for a common cathode dual anode full bridge rectifier to feed a single rail power supply and am getting no voltage increase at all, just the forward voltage drop. Not expected, and won’t give me the needed voltage from this transformer!
Is this how it’s supposed to work without any voltage increase across the full bridge rectifier?
Sounds like the diodes are wired for half-wave rectification instead of full-wave, to give you that result.
Those may be double diodes, common in computer SMPS.
Maybe they packed the wrong ones.
If they are marked, check on line.
Or, with a meter, the outer legs both have same polarity to center leg, that means outer are anodes and center is cathode (or the other way around).
Maybe they packed the wrong ones.
If they are marked, check on line.
Or, with a meter, the outer legs both have same polarity to center leg, that means outer are anodes and center is cathode (or the other way around).
You need a center tap on the secondary to use only a common cathode diode pair.
The negative leg of a FWB rectifier requires a common anode pair instead.
The negative leg of a FWB rectifier requires a common anode pair instead.
Em, I'm using four, centre leg is cathode. Datasheet doesn't seem to indicate double diode, though of course outsides legs are anode. Of course they're soldered in to the board now.
So one leg with common cathode and the other with common anode? I don't see MUR3020 with both options. How are those selected for mirrored legs?
Datasheet
So one leg with common cathode and the other with common anode? I don't see MUR3020 with both options. How are those selected for mirrored legs?
Datasheet
Outside legs are same , cathode or anode, connected to center anode or cathode, basically two diodes with a common center connection.
If the √2 factor is missing, it may simply mean that you have no filter capacitor connected. Even a half-wave rectifier would still give the same output voltage with the capacitor, and if you mess up the CT connection, the factor will be 2 (or 0.5), not 1.4
Bingo, and the winner is... Elvee! I'd not realised the filter cap would affect that. I connected a filter cap and it changed to 1.386 (secondary 22vac > 30.5vdc).
Thank you. Thank you all for pitching in with ideas.
http://www.hammondmfg.com/pdf/5c007.pdf
https://www.sowter.co.uk/rectifier-transformer-calculation.php
i thought these were basic....
https://www.sowter.co.uk/rectifier-transformer-calculation.php
i thought these were basic....
I warmed it would be an ignorant question. With proper linear education on the subject it could have been avoided, and when searching the internet I would have loved to have the Hammond link pop up. On the Sowter page it is hiding in plain sight, shown but not explained as it is on the Hammond page.