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valorous's Achievements


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  1. Thanks audioguru for your quick response. I will try the tips you suggested.
  2. Hi again. I've build the modified circuit. Everything seems to work. The voltage goes up to 34.5V and the current to 3.8A. The op-amps U1 and U2 get very hot with no load, especially U1. I measured the voltage at pin7=46V. Also I used two 2n3055 transistors with 0.33R emitter resistors but one of the transistors gets hotter than the other one. What can I do to fix the problem? Also when I turn the current potentiometer half way the current increases to 0.5A. So when P2 is half turned the current is not half its maximum value. I'm not sure if this is a problem. Thank you for the help.
  3. Hi I've got a bridge rectifier module GBPC2502P 25A 200V. Can I use it in this circuit? Also can I make some measurements on the circuit before placing the op-amps 445AP. It was very difficult to get them so I don't want to burn them. I'm looking for expected voltages at different test points in the circuit. Thank you for your help.
  4. Thank you audioguru for your answers. I've decided to use a 12V fan. Would a heatsinks with thermal resistance of roughly 1 C/W be enough? I'm going to use the unregulated voltage from the circuit to drive the fan, but I'm not sure how to bring the voltage down to 12V.
  5. Hi to everyone I've decided to build the modified version of 0-30V power supply. I've got 30V 160VA transformer and the op-amps OPA445AP. I have BZX85C5V6 zener diodes at home. Could I use this diode instead of BZX79C5V6? Also I'm not sure what type of heatsink to use for the output transistors. I usually shop on www.rswww.com but I don't know what thermal resistance C/W parameter to choose. I would be very glad if someone can suggest some type. Thank you in advance.
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