infinity.o3 Posted July 1, 2005 Report Share Posted July 1, 2005 helo, i new here. and oso new to electronic stuff. ;) i would like to ask how to build a power supply? it is a triple output power supply (o/p= +15v, -15v and -5v) of not more than 15 components. where can i find more about this stuff? any link? i would also want to find a schematic diagram of power supply. thank..!! :) Quote Link to comment Share on other sites More sharing options...
ante Posted July 1, 2005 Report Share Posted July 1, 2005 Hi infinity,Welcome to our forum,Here are two circuits, one with fixed voltage and on with variable. To any of these you can add an LM 7905 on the negative side to get the -5V you require. Quote Link to comment Share on other sites More sharing options...
infinity.o3 Posted July 2, 2005 Author Report Share Posted July 2, 2005 thx.i was wondering are there anymore simply diagram. i cant realli understand it. Quote Link to comment Share on other sites More sharing options...
ante Posted July 2, 2005 Report Share Posted July 2, 2005 Hi again,Sorry but it don’t get much simpler than this, how can I help? Quote Link to comment Share on other sites More sharing options...
infinity.o3 Posted July 3, 2005 Author Report Share Posted July 3, 2005 i also ned to include resistor. but there are no resistor rite? i still need to build a power supply out. hope u could help mi. =)) Quote Link to comment Share on other sites More sharing options...
Guest SM2GXN Posted July 3, 2005 Report Share Posted July 3, 2005 Hi infinity.o3!Going from left to right: 1. Marked 230 volts were the mains cable is to be connected, that side is called primary side.2. F1 is a fuse 33mA/250 volts that one will blow if there is a short in the transformer windings or if there is to big load on the secondary side of the transformer which can be a faulty/shorted component. F1 is important!3. Tr1 transformer with 230V primary and secondary 2X15volts/33mA center tapped meaning if you measure from centertap (line going in the middle marked GND=ground) to one of the outer taps you will get 15volts and if you measure across the outer taps 30 Volts AC.3. D1-D4 As you correctly noted, diodes. These diodes will rectify the AC to DC, the two upper are for the positive/plus side and the lower diodes are negative/minus.4. C1 & C2 are electrolytic capacitors these are filter capacitors, without them you will get an annoying hum. If you live in a country where the line frequency is 50Hz you'll get 100Hz hum and if 60Hz then 120Hz5. IC1 & IC2 are voltage regulators they make sure that the voltage comming out from your power supply wont drop when you connect a load, they stabilize the voltage.7815= 15 volts positive voltage regulator.7915= 15 volts negative voltage regulator.This power supply is for light loads meaning that you can't draw much current from it.Bjorn Quote Link to comment Share on other sites More sharing options...
ante Posted July 3, 2005 Report Share Posted July 3, 2005 Hi infinity,Just adding some to Bjorns detailed answer:To your first question; there are no resistors needed in this circuit!You can learn more about the voltage regulators here: http://www.aleeanne.org.uk/datasheets/datasheet2/LM7815.PDFYou can use the same circuit for heavier load by using a higher rated transformer and maybe slightly bigger caps if you need more current.I don’t know where you live but it’s possible that you don’t have 230VAC mains but 120 VAC or perhaps something else. Quote Link to comment Share on other sites More sharing options...
Kevin Weddle Posted July 3, 2005 Report Share Posted July 3, 2005 In another post long ago, I had this idea. A voltage multiplier, which is typically low current, makes a good DC source from an AC or analogue signal. Of course in order to make them high current, you need high capacitance. High capacitance makes them low voltage capacitors. Therefore, it is only impractical to take a high voltage source, use some capacitors and diodes, and realize a DC source. A transformer with capacitors and diodes is used in it's place. Quote Link to comment Share on other sites More sharing options...
majorabak Posted July 11, 2005 Report Share Posted July 11, 2005 ;) hey sorry... i m also new here... how abt the -5V output?Where do i put it? Quote Link to comment Share on other sites More sharing options...
ante Posted July 11, 2005 Report Share Posted July 11, 2005 Hi Major,Welcome to our forum.Just add a 7905 to the negative side where the 7915 is. Quote Link to comment Share on other sites More sharing options...
timothy Posted July 12, 2005 Report Share Posted July 12, 2005 Hi ante,the electronics god!Just want to add on to the question.Do you mean adding 7905 beside the 7915?Then do i need to add space for the negative 5 output?Sorry for the trouble because i very new and blur to electronic stuff. Thanks ;D Quote Link to comment Share on other sites More sharing options...
infinity.o3 Posted July 12, 2005 Author Report Share Posted July 12, 2005 hey. sorry so long den reply. hee. my teacher is giving mi LM7805. but at the circuit u gave is LM7915. is the two the same? the fuse 33mA. why my teacher give is 1A? C3, C4, C5 &C6 is wad? all is capactior? btw, my teacher onli will give us 3 capactitors. Quote Link to comment Share on other sites More sharing options...
thefinalaeon Posted July 12, 2005 Report Share Posted July 12, 2005 hello infinity lol u from poly ar? wad poly? my teacher also ask me do same project as u for term break ahah... Quote Link to comment Share on other sites More sharing options...
loVeheb3 Posted July 12, 2005 Report Share Posted July 12, 2005 hi.... i am oso doing that project... i'm frm Tp... any here noe how to do the project pls tell mi thx..... n which is the schematics diagram? Quote Link to comment Share on other sites More sharing options...
ante Posted July 12, 2005 Report Share Posted July 12, 2005 Hi timothy,You can do this one of two ways; either you connect the input of the 7905 to the input of the 7915 or to the output of the 7915. Then connect the ground pin of the 7905 to the 0v rail and last the output pin of the 7905 will be your -5V output. Add a capacitor on the input side as well as to the output side just like it has been done with the other regulators. Quote Link to comment Share on other sites More sharing options...
infinity.o3 Posted July 13, 2005 Author Report Share Posted July 13, 2005 hello infinity lol u from poly ar? wad poly? my teacher also ask me do same project as u for term break ahah...eloo. i from tp. i bet u oso from tp. ;Dhv u finish ur project? do u noe how to write 'the explanation on the operation of the power supply'? Quote Link to comment Share on other sites More sharing options...
timothy Posted July 13, 2005 Report Share Posted July 13, 2005 Thanks ante!hi everyone,i also from tp.I believe everyone is busily doing your EPT project.When you serch internet,there is no clue on the triple output supply and it goes the same for books.Any suggestion must post wor.. Quote Link to comment Share on other sites More sharing options...
st0rmagneto Posted July 13, 2005 Report Share Posted July 13, 2005 Hey !! Hi !! Same here , doing tt project .. If anyone of you had gotten the schematic diagram , please kindly email me at [email protected] . Thanks !! :) Quote Link to comment Share on other sites More sharing options...
thefinalaeon Posted July 13, 2005 Report Share Posted July 13, 2005 sian... me also from tp lor... i dunno how to do leh... i onli found the datasheet for the 4 components tts all... btw ante... u give us 7915 and 7905... our teacher give us 7815 and 7805... any diff btw them? please kindly help :) Quote Link to comment Share on other sites More sharing options...
majorabak Posted July 13, 2005 Report Share Posted July 13, 2005 erm ... wad if i add the 7905 under the C6 capacitor? Is that correct? ;D Quote Link to comment Share on other sites More sharing options...
majorabak Posted July 13, 2005 Report Share Posted July 13, 2005 TIMOTHY OI! U HONG TUAN RITE AHAHAHAH... I Kenneth seh... haiz tis stuff is making go nuts... help ??? :o Quote Link to comment Share on other sites More sharing options...
majorabak Posted July 13, 2005 Report Share Posted July 13, 2005 hey loveheb3 ? do i noe u? i also from tp... hmm ... lks like the ept stuff very stress Quote Link to comment Share on other sites More sharing options...
majorabak Posted July 13, 2005 Report Share Posted July 13, 2005 aniwae why do i add my extra capacitors to my 5V regulator? and also ... are C5 and C6 electrolytic capacitors too? sorry i blur sia... plz reply back ty very much... Quote Link to comment Share on other sites More sharing options...
infinity.o3 Posted July 13, 2005 Author Report Share Posted July 13, 2005 omg, all from tp. "-.-wat if teacher found out tt our cct is the same. haha.do ur guy noe how to write the report? who ur teacher ar? Quote Link to comment Share on other sites More sharing options...
thefinalaeon Posted July 13, 2005 Report Share Posted July 13, 2005 me frm class 24 lol Quote Link to comment Share on other sites More sharing options...
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