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About costa

  • Birthday 11/12/1976

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  1. if anything can go wrong it will go wrong...murphy's law... >:( >:( >:( my project worked fine all the time... :D :D :D it was not faulty in any way...current regulator works fine....it delivers over 4Amps on 30Volts... my mistake was that i used chinese,piece of shit,analog ampermeter (that i planed to use fixed on my power suplly) that was inaccurate, to say at least... this ampmeter displayed 2.2 amps when there was 4amps for real... i feel like an idiot...wasted so much time on trying to solve a problem that wasnt there... sorry to you all that i bothered, especialy you audioguru...i know i've been a bit of a drag... :-[ :-[ :-[ p.s. does anybody have a shematic of a led display digital ampermeter with range 0-5 amps and 0.1 accuracy...thanx...
  2. hi audioguru... my projects transformer is 150VA...my C1 is 10000mikroF 50V mounted on pcb... my rectifier is MB356 35A 600V fast recovery... i checked every connection on pcb...all is ok...i could not mistaken the conection of elements anywhere beacause i use the orginal pcb design,did not modify it...i used the parts list posted by you in this forum... so the problem is that i cant get the proper amperage on output... i think that some values in current limiting section are false by design...the amp pot is on maximum yet it limits the curent to 2.2 amps...with whatever the voltage required for the load... my question:what can i modify to get more amp control on output??? please help... has anyone succeded to build this suplly and got 3A on output???
  3. my suplly still lacks power... i connected two light bulbs in parallel to see if it goes to 3 amps... it doesnt...since one draws 1.5Amps on 32V two sould draw 3 amps... current limiter of the suplly limits this load to 2.2A on 18Volts...with both pots to max... please help...
  4. tnx audioguru... found the problem...i misconnected the pins of Q2... now i can get full power on the output... i messured the voltages that u asked... my load draws 1.5A on max.output voltage of 34V...current limiter lights the led when utput is shorted but it doesnt turn the output off (my a-meter shws 2 amps)...is this normal??? Q2 base , 34.6V noload , 34.5V loaded Q2 emiter , 34.1V noload , 33.7V loaded Q2 collector , 40.2V noload , 35.5V loaded U2 pin6 , 34.6V noload , 34.4V loaded U2 pin3 , 10.8V noload , 12.0V loaded U1 pin6 , 10.6V noload , 12.1V loaded U1 pin7 , 40.3V noload , 35.5 V loaded U3 pin6 , 39.3V noload , 34.7V loaded U3 pin7 , 40.3V noload , 35.5V loaded i guess this values are ok...your opinion??? btw. i used BD243C for Q2 and Q1
  5. current limiter doesnt work when output is shorted >:( >:( >:( voltage on pin6 of U2 drops from 42V (without load) to 25V (with load) >:( >:( >:( please help :'( :'( :'(
  6. the current limiter works fine...led lights when pot goes to minimum (with the load)... i didnt try shorting the output...will do...will messure the v on pin 6 of U2.... thanks....
  7. hi... i must say that in first tests on this supply (with orginal parts list) it worked fine...the load (24V 50W light bulb) went over 30V and 2.4A...of course it had heat problems... then i changed the project with updated part list because i need sure 3A with 30V output...managed to obtain OPA445 for about 10 euro a piece...put two 2N3055 in paralleland so on...at first i spotted an error since i mistaken the value of R22 and mounted an 3.9Om instead of 3.9kOm...of course i burned the Q3 and LED...changed the Q3 and R22... i still have a problem... suplly gives output of 0 to 34 volts without any load...thats fine... btw. i have 150VA 32Volt secondary on my trafo... when i put load (24V 50W light bulb) my max output goes only 21V with 1.2A through this load... i messured 44V on C1 without load and 40V with load... why cant i get more power with the load??? could i damaged anything else with my error on R22??? please help...anyone...
  8. hi... a question... has anyone found another complementary OP's for this project... OPA445 is very expensive and MC34071 and TLE2141 cant be found in croatia... please help...(mixos , audioguru , anyone)
  9. thanks audioguru... sorry i didnt mention that i use stronger transformer as specified... ;D but i ask again for the cap C7 (not C1) if it could or should be of a bit larger capacity??? thanks... btw. audioguru, i am searchin for a timer circuit that would turn off my aquarium lamp in the evening 22.00h and turn it on in the morning 07.00h,every day...have you heard of something like it???
  10. hello guys!!! :D :D :D this is my first post here, since i registred few days ago... i built this power supply with org.specs and it works fine...2.5 A with almost 34V.... i am going to modify it so it can hold more than 3A output current as suggested by you all... I read all the posts about this PSU and only thing not so clear to me is the emiter of Q1... does it go on junction of C1- and R7(negative input) or on the junction of R7 and C7(negative output)... Also should C7 be of a greater value??? Please help...
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