Electronics > Beginners
Help with overload protection
Jwillis:
Sorry that this thread changed from the original subject .
--- Quote from: Ian.M on September 27, 2019, 09:32:14 pm ---If you need asymmetric positive and negative rails, you cant put the secondaries in series before the bridge rectifier. Symmetrical rails from a bridge rectifier + center tapped winding is a special case. Therefore you need to use a second bridge rectifier and put the bridge rectifier outputs in series.
Edit: just seen your diagram of exactly that.
It would be helpful if you can tolerate a lower voltage negative regulated supply for the OPAMPs (in the -8V to -10V range) so you can use the unregulated auxiliary supply for the 12V fans without over-voltaging them too much or needing to waste power in diode droppers or a regulator for the fan supply. If you *NEED* a full 12V, then you'll have to use a LDO regulator for it and only have just enough headroom to cope with a +/-10% line voltage variation, to minimise the power wasted dropping the voltage for the fans.
--- End quote ---
I plan to scrap the original negative rail configuration for the newer approach. I haven't wound a new secondary yet so I'll have to work out an appropriate voltage to work with .This will simplify the negative rail and be a little more stable.As you suggested I do have LDOs that just may work.
Thanks for the input and advice .It's really appreciated.
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