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    0-30 Vdc Stabilized Power Supply

    Sorry. I was aware of the pullup resistor. I will stop from here and stay with the standard project. I will stick with the lm311 and a lm35 for cooling the heatsink. Once again, thank you for your help and patience, audioguru.
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    0-30 Vdc Stabilized Power Supply

    I I was thinking about the tap selection circuit being done before the rectifier diodes and filter capacitors. This image relates to a similar aproach using the lm338. Since the mc34071 needs a stable 40v supply and -1,4v. Another 28vac 600ma transformer is used for powering the opamps and...
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    0-30 Vdc Stabilized Power Supply

    Hello everybody. What modifications should i consider for making this project? My idea is: 1- A huge transformer with two 28v secondarys. One secondary has a low current for only driving the current and power regulation. Another secondary will deliver the high current and has multiples taps...
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    0-30 Vdc Stabilized Power Supply

    Hahahaha. I promise i will make a better one.
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    0-30 Vdc Stabilized Power Supply

    Sorry, audioguru. My post sounded like i was describing how the circuit should work but i was just explaining the behavior of the opamps. None of the 3 opamps were working as intended. The problem was caused by my lack of atention while copying the schematic to Kicad. The opamp footprint for U2...
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    0-30 Vdc Stabilized Power Supply

    Sorry. You're right. I confused the order of the ICs. U1 (reference voltage) outputs 33v and U2 (voltage control) outputs 0,640V to the base of the BD139.
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    0-30 Vdc Stabilized Power Supply

    U3 only outputs 0,640 volts. When the voltage control pot is rotated to the left or right, the variation in the readings are minimal. The voltage only raises to 10v when U3 gets too hot. U1 outputs 33v and also gets hot. RV2 has no effect on the readings.
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    0-30 Vdc Stabilized Power Supply

    Wow! After long 4 months of waiting, my package with five TLE2141CP finally arrived from China. And for my "surprise" none of them worked. Both U1 and U3 got extremely hot and began to smell. Turns out two resistor got burned!! Just minutes ago i found a store in my country that sells the...
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    0-30 Vdc Stabilized Power Supply

    Thank you, Tintin. Adding another 2k2 resistor in parallel solves the problem. Now the rectified voltage is 40,5 VDC and will not rise.
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    0-30 Vdc Stabilized Power Supply

    Then i should assume that my 30.5VAC transformer has a number of widings for a 29.5VAC. The widings are at a ratio of 2,44 turns per volt. So i need to remove 2 or 3 turns to get something near the ideal 28AVC.
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    0-30 Vdc Stabilized Power Supply

    Hello. I have a question about the rectifier part of this project. I recently made a transformer and a rectifier board that outputs the GND, 30VDC and -1,4VDC lines. Since the winding was made by hand, the output voltage got a little off. Instead of a 28AC output, i got something around 30,5AC...
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    0-30 Vdc Stabilized Power Supply

    What is the consensus about the voltage spikes discussed on older posts? REV8 adds a darlington transistor to solve this problem. But even after that, other solutions are still being presented for the same problem.
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    0-30 Vdc Stabilized Power Supply

    Thank you. I will choose this project in that case.
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    0-30 Vdc Stabilized Power Supply

    I found this. Since the same model number is shared by other 4 brands. I can't tell if the actual hardware still true to the schematic.
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    0-30 Vdc Stabilized Power Supply

    I'm referring about this model.
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    0-30 Vdc Stabilized Power Supply

    For months I've been reading threads about this project to get some confidence boost in building my own.  But at first, my plan was to buy one of these cheap chinese power supplies that provides 30v at 5Amps. My question is about the stability of those chinese power supplys compared to this...
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