http://i42.tinypic.com/2jite.png
Despite what the pic says, i'm on 125v mains here
ok so i'm wanting to build this as a fun project and possibly use it as a bench top power supply if it ends up working...Surprisingly enough, i happen to have all the parts for this except for the two transistors. I checked the specs out on these things and they are rated at 700v, 15A, and have a Hfe of 2.5....the two transistors that i do have that are rated like that are broken, unfortunately:/....the only other power transistors i got are these E13009 that i stripped from an old broken smps....they are only rated tho at 400v, 12A, and a Hfe of 8
here is the datasheet if you are wanting to look at it...click the little blue link next to download in the box in the middle
http://www.datasheetcatalog.com/datasheets_pdf/K/S/E/1/KSE13009.shtml
I'm figuring that because here in the U.S we have 125v mains and the circuit is built to withstand 230v mains, i believe it would be ok to use the E13009's since 125v is only a little more than half of the 230v the circuit calls for...theoretically i can cut the transistor rating by a little less than half right? and that would come out pretty close to the 400v rating the E13009's have. of course though i will have to add protection diodes to the E13009's since they don't have them built in like the two the circuit calls for.
Despite what the pic says, i'm on 125v mains here
ok so i'm wanting to build this as a fun project and possibly use it as a bench top power supply if it ends up working...Surprisingly enough, i happen to have all the parts for this except for the two transistors. I checked the specs out on these things and they are rated at 700v, 15A, and have a Hfe of 2.5....the two transistors that i do have that are rated like that are broken, unfortunately:/....the only other power transistors i got are these E13009 that i stripped from an old broken smps....they are only rated tho at 400v, 12A, and a Hfe of 8
here is the datasheet if you are wanting to look at it...click the little blue link next to download in the box in the middle
http://www.datasheetcatalog.com/datasheets_pdf/K/S/E/1/KSE13009.shtml
I'm figuring that because here in the U.S we have 125v mains and the circuit is built to withstand 230v mains, i believe it would be ok to use the E13009's since 125v is only a little more than half of the 230v the circuit calls for...theoretically i can cut the transistor rating by a little less than half right? and that would come out pretty close to the 400v rating the E13009's have. of course though i will have to add protection diodes to the E13009's since they don't have them built in like the two the circuit calls for.
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Good news bad news. The transistors will probably be OK with protection diodes. However... you've got half the volts overall and a 20% increase in frequency coming in the C6/R4 start circuit which may give starting problems. If you leave the transformer windings the same you won't get the same current at the output unless you tinker with either the primary or secondary windings or both. Also there may not be enough current to saturate the transistors (via the base windings) although the increased Hfe of the E13009 may help there. Think you may be in for some suck it and see transformer design.