Hero999 Posted November 5, 2009 Report Share Posted November 5, 2009 i know ...i will build 2 Supply and than how i have to connect the Outputs to get +-30V ?Connect the two power supplies in series and use the point where the two supplies are joined as the 0V point. Quote Link to comment Share on other sites More sharing options...
nand Posted November 6, 2009 Report Share Posted November 6, 2009 + +- - ??or+ - - + ?thx ! Quote Link to comment Share on other sites More sharing options...
tjaartk Posted November 6, 2009 Report Share Posted November 6, 2009 Hi allFirst time for me on this site. I have built this and it works grate. By the way very new to electronics, I have started it as n hobby at 34 (last year). I want to built the two vertions off the amp/volt meters the show with the project. where can i find the scematics and so on for the bords shown and could some one please tell me in laymens terms how the second lcd display one works. Would epreciate it. Quote Link to comment Share on other sites More sharing options...
tjaartk Posted November 6, 2009 Report Share Posted November 6, 2009 PS the boards shown of Sam Carmel & and the other one of (programable IC?) Quote Link to comment Share on other sites More sharing options...
Hero999 Posted November 6, 2009 Report Share Posted November 6, 2009 + +- - ??or+ - - + ?thx !What do you think? Quote Link to comment Share on other sites More sharing options...
nand Posted November 6, 2009 Report Share Posted November 6, 2009 How i have to connect it ? how its right ? how i can get +-30V ?This ? OR This? _Supply1_ _Supply2_ _Supply1_ _Supply2_ | | | | | | | || | | | | | | || | | | | | | ||_+____- __| | __+__-__ | |_+____- __| | __-__+__| | |__________ | | | |____________| | | | | | | | | | | | | | |_Voltage?___|_Voltage?_| |_Voltage?____|_Voltage___| Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 6, 2009 Report Share Posted November 6, 2009 Nand, are you blind? Quote Link to comment Share on other sites More sharing options...
carlos206 Posted November 7, 2009 Report Share Posted November 7, 2009 The answer is Supply1_ _Supply2_ | | | | | | | | | | | | |_+____- __| | __+__-__ | | |__________ | | | | | | | | |_Voltage?___|_Voltage?_| Good luck! Quote Link to comment Share on other sites More sharing options...
nand Posted November 7, 2009 Report Share Posted November 7, 2009 if I Connect + with - the Cicuit ist shorted ? thx for all info now i will build 4 Supply... Quote Link to comment Share on other sites More sharing options...
Hero999 Posted November 7, 2009 Report Share Posted November 7, 2009 How can it possibly be shorted when it's clearly open circuit?If you need to ask such questions then you obviously don't have enough experience to build it.I suggest you read more about basic circuit theory and Ohm's law and basic before building this project.. Quote Link to comment Share on other sites More sharing options...
nand Posted November 7, 2009 Report Share Posted November 7, 2009 last question.... Quote Link to comment Share on other sites More sharing options...
carlos206 Posted November 7, 2009 Report Share Posted November 7, 2009 Hi can I use the op amp LF355 instead MC34071 or TLE2141? i saw that Vcc max is 44. thx Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 7, 2009 Report Share Posted November 7, 2009 Hi can I use the op amp LF355 instead MC34071 or TLE2141? i saw that Vcc max is 44. thxThe National Semi LM355 is obsolete and has not been made for 11 years. Its max allowed supply was only 36V but was 44v for the more expensive LF155.They will not work in the latest circuit because their input common-mode range does not go as low as the MC34071 or the TLE2141. The LF355 is almost the same as a TL081. Quote Link to comment Share on other sites More sharing options...
Hero999 Posted November 7, 2009 Report Share Posted November 7, 2009 last question....What do you think?The circuit will obviously work as long as you're aware that the supplies on the right will not be isolated from each other and if you don't know what that means then I suggest you do some more research before building it. Quote Link to comment Share on other sites More sharing options...
nand Posted November 7, 2009 Report Share Posted November 7, 2009 hmmmm...you think i`m arent allowed to connect the the 2 GND signals on the right side when i use the left side in series connection right ? Quote Link to comment Share on other sites More sharing options...
corsa Posted November 23, 2009 Report Share Posted November 23, 2009 Hello everyone.I saw all posts, but my english is poor, so if i will be repetitive, i'm so sorry in advance.I would like to make this PS and i have the pcb for old version maked yet and all components, and found now this discussion about "problems" of original version. I understood, one of the problems are some components like 2N2219 over-heats, but i just need 24v and 2,5A max, so i have one transformer of 24V - 3A. This is critical for this values? I can change too:R1 = 2,2 KOhm 2WR2 = 82 Ohm 2WR7 = 0,47 Ohm 10WFor dissipate more heat and dont burn.So only with this changes i can make the old version without burn problems?Note: I don't need the 30V 3A max, just 24V 2,5A is enough for me.Thanks in advance and sorry for my bad english.My best regards,Andr Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 23, 2009 Report Share Posted November 23, 2009 Replace the tiny 2N2219 driver transistor with a BD139 power transistor on a proper heatsink.For an output of 2.5ADC the 24V transformer must deliver 33.9V at 2.5A which is 84.8VA. Then a 24V/3.5A transformer must be used.The original TL081 opamps have a max allowed total supply voltage of 36V. But with a 24V transformer two opamps have a total supply of 41.7V without a load. 44V opamps are available.The single 2N3055 output transistor must dissipate 36V at 2.5A when the output is shorted and set to 2.5A. This is 90W which will overheat the transistor even if it has a huge heatsink.It needs two output transistors to share the heat.The offset voltage adjustment parts are wrong and connect to the wrong voltage. Quote Link to comment Share on other sites More sharing options...
corsa Posted November 27, 2009 Report Share Posted November 27, 2009 Hello Audioguru, so its bether i make the last version ;DHave you the last version converted to PCB diagram for print?Regards,Andr Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 27, 2009 Report Share Posted November 27, 2009 hmmmm...you think i`m arent allowed to connect the the 2 GND signals on the right side when i use the left side in series connection right ?We do not know what you are talking about. Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 27, 2009 Report Share Posted November 27, 2009 Hello Audioguru, so its bether i make the last version ;DHave you the last version converted to PCB diagram for print?Some people posted their pcb design but this website crashed and they are gone.I didn't save them. Quote Link to comment Share on other sites More sharing options...
xsyt Posted November 28, 2009 Report Share Posted November 28, 2009 I have 60VA transformator (230 / 22VAC - 2,8A). Is that enough for original regulated power supply ( here )? How many ampers fuse I need for that transoformator on primar side?Thanks. Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 28, 2009 Report Share Posted November 28, 2009 Hi Zsyt,The transformer specified in the original project is overloaded and might cause trouble.The 24VAC is rectified and has a peak voltage of 34V. Then if the output has a load of 3A the transformer must provide 34V x 3A= 102VA.The voltage on your transformer is too low at 22V and will have a peak voltage of 31V. Then your transformer is overloaded if the DC current from the project exceeds 1.9A.Your max output voltage at 1.9A will be about 22.5V.The fuse should blow if the transformer is overloaded. 60VA/230V= 0.26A. Maybe use a slow blow 0.3A fuse. Quote Link to comment Share on other sites More sharing options...
xsyt Posted November 29, 2009 Report Share Posted November 29, 2009 Thanks for that anwser. How I can connect the potentiometers for regulate voltage with two potentiometets (one for fine regulate, one for sharp). Is the schematic below okay? Quote Link to comment Share on other sites More sharing options...
redwire Posted November 29, 2009 Author Report Share Posted November 29, 2009 Zsyt may be able to use the transformer with the revised design posted at the beginning of the thread. RV3 is used to regulate the max output to stay within the parameters of the transformer and board. Quote Link to comment Share on other sites More sharing options...
corsa Posted November 29, 2009 Report Share Posted November 29, 2009 Hi dear redwire, i'm looking for last version pcb design but i can't find them, i just have the original pcb design.Have you the last one or a modified version pcb design?Regards Quote Link to comment Share on other sites More sharing options...
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