Yeah, I forgot to add that. The part I would really like to do is re-wind the transformer to get anywhere from +/-12 to +/-24V output. The trick there would be to find an AT or ATX box whose output section had the room for a LCLC output on BOTH of the +12V and +5V outputs.
Fallin' asleep at the keyboard, so I'll sign off for now.
Fallin' asleep at the keyboard, so I'll sign off for now.
reply
hi friend,
It seems that u cannot get more current by simply replacing a diode with higher rated ones since it also depends on transformer winding thickness. The -12v and -5v winding are usually lesser in thickness. You may need to change the winding also. It requires greater care in doing so.
hi friend,
It seems that u cannot get more current by simply replacing a diode with higher rated ones since it also depends on transformer winding thickness. The -12v and -5v winding are usually lesser in thickness. You may need to change the winding also. It requires greater care in doing so.
Re: reply
There are no specific -12V and -5V windings on the main transformers of classic AT and ATX supplies. There is a set of push-pull windings which are used both for + and - outputs. Furthermore, the 12V windings (7 turns) are actually tapped at 3 turns to obtain 5V. You may sometimes find specific windings for -12V and -5V in the output inductor (yellow toroid), but not all circuits use them.
In other words, the transformer found in most AT and ATX power supplies is ready to produce up to +-20V without rewinding, altough gentle PCB rework may be required sometimes.
I would really like to modify some old ATX power supply to get +/-20V and post detailed explanations and pictures of the process so that other people can repeat it, but I'm currently very busy with commercial projects (maybe in a moth or so...)
rejithcv said:
There are no specific -12V and -5V windings on the main transformers of classic AT and ATX supplies. There is a set of push-pull windings which are used both for + and - outputs. Furthermore, the 12V windings (7 turns) are actually tapped at 3 turns to obtain 5V. You may sometimes find specific windings for -12V and -5V in the output inductor (yellow toroid), but not all circuits use them.
In other words, the transformer found in most AT and ATX power supplies is ready to produce up to +-20V without rewinding, altough gentle PCB rework may be required sometimes.
I would really like to modify some old ATX power supply to get +/-20V and post detailed explanations and pictures of the process so that other people can repeat it, but I'm currently very busy with commercial projects (maybe in a moth or so...)
Try FEP16DT and FEP16DTA from Fairchild (the D letter may be actually from A to J as it specifies voltage rating, D=200V, A=50V, J=600V). The A suffix is similar to the R suffix of the On-Semi diode and specifies common anode instead of the standard common cathode (very useful for the negative rail). Check Fairchild website.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.