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nemeszoli

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Everything posted by nemeszoli

  1. Hy, I don`t realy understand why but, by changing the place where the 22000uF C1 capacitor is connected my power supply seems to be working now. I designed a connector for C1 wich was connected on, and in my earlier post I attached a picture of the output voltage form (square wave), now I connected C1 directly on the wires connecting the rectifier (black and red on the picture) and this way the output voltage looks nice, the triangle wave is the voltage on C1, but it doesn`t seem to influente the output voltage. I gues the problem should be in my PCB design
  2. Hy, I made some measurements on my power supply but unfortuneatly I saw that I have a ripple of about 0,8V ??? at 6A tested with a load of 1.5ohms. I have a transformer with 26V output, I would like to have on the power supplys output at least 24V without ripple I tried also using a 22000uF capacitor but the result was the same as with a 10000uF one
  3. Hi audioguru, I used TLE2141 opamps ordered from farnel.com. Without a load, on R7 I have 2,2mV, wich means about 10mA passing trough it, I think this is normal because the current supplying U1 is passing trough R7 and 0V wire. I tried taking out U1 from the circuit, in this way there vas no voltage on R7 so I think, with this design it is normal to have some current on the 0V wire
  4. Hi everyone, I finished building this power supply with the three 2N3055 transistors version, but I couldn`t find 0,27/10W ohm resistor for R7 only 0,22 ohm but it works really nice, I measured the output current in short circuit it is adjustable from 0 to 11,38A ;D, but with the current setting trimmer it can be calibrated to a smaller output current, the minimum output voltage is about 50mV cannot be adjusted with RV1 not even if I replaced C7 with a tantalum capacitor. I had the same problem as some other guys, when the current limit pot. is turned to min. the current limit led lights up, I thougth if U3 is a comaparator on U3 pin 3 is the reference voltage for the current control, on pin 2 the voltage without a load was 10.6 mV, and when the current control pot. is at min. on U3 pin 3, I had 8.4 mV (the compared value was bigger than the reference value) from this voltage difference the led was lighting up, so I replaced the 33ohm R17 to 100ohm ;D (I don`t think I have to change anything else, correct me if I am wrong) so in this case the voltage on U3 pin 3 with the current set. pot. at min. is 11.4 mV finaly the led does not light up when the current set. pot. is at min. :), but in my case from the voltage difference between pin 2 and 3 on U3 the minimum adjustable current is about 4 mA, which I don`t mind. I designed a board in eagle and I would like to make a 7 segment volt and ampere meter using PIC, I`ll upload some pictures of my project soon...
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