Power supply advice

Discussion in 'The Projects Forum' started by jm-a, Dec 26, 2014.

  1. jm-a

    Thread Starter Active Member

    Oct 20, 2010
    Hi all,

    Happy new year for all members first.

    I only want advices on this power supply:


    1° For TL081 ampli op, is it better to use , MEA1D1512SC outputs for + Vcc and -Vcc?
    Pin 6 from MEA1D1512SC ?

    See Schematic

    2° Replacing TL081 by OPA548 a better choice, so without MEA1D1512Sc, of course?

    http://www.reichelt.de/Heat-Sinks-profile/V-6506G/3/index.html?ACTION=3;ARTICLE=147280;SEARCH=OPA 548 T

    3° Transo replaced by RKT 30030 30V 10A See RK.pdf

    http://www.reichelt.de/ADW/0/0//index.html?ACTION=3;ARTICLE=40440;SEARCH=RKT 30030

    4° Bridge rectifier : KBPC-Serie-HYE-Datasheet and

    MBR2035-2060CT or diodes like BY214-400 for D5 D6 ?


    5° I'd want to use 2 or 3 2N3055, how to connect them, in parallel with 0,1 Ohm resistor 5W...

    6° Heatsink for 2N3055 , right choice, after some machining?

    http://www.reichelt.de/Heat-Sinks-profile/V-6506G/3/index.html?&ACTION=3&LA=2&ARTICLE=22272&GROUPID=3383&artnr=V 6506G

    Happy new year for all and thanks a lot.

    Last edited: Dec 26, 2014
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
    A few problems.
    The little diodes are used to generate a small negative voltage for the op amps so their output can go all the way to ground. So if you use them you don't need the extra little power supply. But if you use a 30 volt transformer the peak output will be 42 volts. To high for most op amps. You could use an LT1014. It's ok to 44 volts.
    You want an op amp that goes close to the negative supply so the LT part would be a better choice than the TL081.
    The problem with high voltage linear supplies is that when set to low voltage the rest of the power is "burned" in the 3055's. So if you have 42 volts in and say 5 volts out at 10 amps the 3055's dissipate 370 watts. Way to much.
    I don't know what you need from the power supply, but think about making it a 15 volt 5 amp.
    jm-a likes this.
  3. jm-a

    Thread Starter Active Member

    Oct 20, 2010
    Thanks a lot ronv, for you reply.

    I only want a precise lab power supply, 0-30V and 5 A .

    Last edited: Dec 30, 2014