[0-30V Stabilized Power Supply]

works awesome, thank you very much!

Next on my list: Upgrade to 8A version  ;D

P.S. use PTC! They limit the output current in case of a transistor melt down

[0-30V Stabilized Power Supply]

upgraded the psu and put in the 3 TLE2141. Pin 3 of U2 has now an input voltage from 0-11,2V, just like it has to be, but the output voltage at pin 6 of U2 is 33V when voltage at Pin 3 of U2 is higher than 0V and is 0V when Pin 3 of U2 is 0V. When the output voltage of pin 6 is 0V, then the voltage at the output of the power transistors is 3,5V. The across pin 4 and 7 of U2 is 35V. Please help, i have no clue  ???

EDIT// Nevermind, forgot to connect the Cathode of D11 (the Minus -) to the +-Output

Works like a charm, although it is only decreaseable to 100mV but I dont care :D :D :D :D

[0-30V Stabilized Power Supply]

Something is wrong in the U3/R7 circuit.

Ah, finally found it, I mixed up the collector and emitter of the PNP transistor, can't believe I was that stupid, I should really use PNP more often  ::)
I guess this explains most of the led problems in this topic.

No.
A 1N4734A zener diode is rated at 500mW. But its voltage is rated when the current is 45mA which is much too high. It might not regulate when its current is only 1.5mA or 5.6mA.
1N752A and 1N5232B zener diodes are also rated at 500mW. But their voltage is rated when the current is 20mA which is also too high.
1N5994B and BZX79C5V6 zener diodes are also rated at 500mW but their voltage is rated when the current is 5mA which is good.

Of course i choosed one with 5mA, now my psu should finally work and with the new op amps even better. Thank you very much for your patience!

[0-30V Stabilized Power Supply]

The voltage setting pot should feed 0V to 11.2V to U2. If it is 0V but the output of the supply is 17V then maybe Q2 or Q4 have their pins mixed up and are acting like a zener diode.

Q4 was broken and is now a diode :D

U3 is the current regulator that is supposed to act like a switch. when it does not regulate current then the LED is supposed to be turned off. When it regulates the current then the LED is supposed to be completely turned on.

so i need to increase the resistance for the diode?

The zener diode should be able to work at a low current. You probably used a zener diode thast works at a high current. R4 has a value that is too high since it limits the current in the zener diode to only 1.2mA. Use a BZX79C5V6 zener diode that is rated at 5mA and change R4 to 1k ohm for a current of 5.6mA.

you're right, i got a 1,3W diode, i'm gonna buy a 500mW tomorrow

The absolute max allowed supply voltage for a TL081 is only 36V so yours have a higher voltage that might destroy them.

TLE2141CP   3 of 3 part(s) Shipped   10 Feb 2010   i love Texas Instruments :D

[0-30V Stabilized Power Supply]

Hi guys, i assembled the first version of this p.s.u. and found the improved version just today, sampled the TLE2141 today and then i will update my board. But my first version does not work: Potentiometer for voltage regulation only changes the voltage from 34V to 17V when he hits zero ohm, also the led is glowing the whole time and when i set the current pot to nearly full limitation and add a load it glows brighter. Also the voltage at D8 (the 5,6V Zener Diode) is only 4,6V and the output of U1 is 9,2V. Are my TL081 broken or don't they work on this voltage correctly, U3 and U2 have about 39V and U1 34V? (I tested them in a test circuit afterwards, seemed not to be damaged).

thank you in advance