Building a transformer
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From: Tim Wescott on 8 Aug 2006 18:46 Jim Thompson wrote: > On Tue, 08 Aug 2006 14:48:15 -0700, Tim Wescott <tim(a)seemywebsite.com> > wrote: > > >>Jim Thompson wrote: >> >>>On Tue, 08 Aug 2006 21:19:21 GMT, "ian field" <dai.ode(a)ntlworld.com> >>>wrote: >>> >>> >>> >>>>"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote in >>>>message news:99uhd21d83biuj4122hfrv1p47k4gip41h(a)4ax.com... >>>> >>>> >>>>>On Tue, 8 Aug 2006 13:44:27 -0700, "RST Engineering \(jw\)" >>>>><jim(a)rstengineering.com> wrote: >>>>> >>>>> >>>>> >>>>>>What primitive semiconductors did you use in the output stage, or was it a >>>>>>toob device? Did we have 2N3055s in '75? I don't memember. >>>>>> >>>>>>Jim >>>>>> >>>>> >>>>>[snip] >>>>> >>>>>I'm trying to remember what semiconductors I used. But, IIRC, >>>>>2N3055's *were* available around that time. >>>>> >>>>> ...Jim Thompson > > >>>>Was it Ge or Si ? >>>> >>> >>> >>>It was Silicon. I didn't use any Germanium power devices since I >>>boosted my car radio back when I was a junior in high school. >>> >>> ...Jim Thompson >> >>Correction: it _is_ silicon. >>http://www.onsemi.com/pub/Collateral/2N3055-D.PDF. >> >>Digi-Key has them for $2.10 a pop, in the TO-3 case, no less. > > > I said it was silicon. The Ge device I used in HS was a Delco > doorknob power device. I did 10W class-A ;-) > > ...Jim Thompson I was only taking issue with your tense -- the 2N3055, while venerable, appears to be in current production. So it's an 'is' part, not a 'was' part. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Posting from Google? See http://cfaj.freeshell.org/google/ "Applied Control Theory for Embedded Systems" came out in April. See details at http://www.wescottdesign.com/actfes/actfes.html
From: Dave Plowman (News) on 8 Aug 2006 19:00 In article <99uhd21d83biuj4122hfrv1p47k4gip41h(a)4ax.com>, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote: > >What primitive semiconductors did you use in the output stage, or was > >it a toob device? Did we have 2N3055s in '75? I don't memember. > I'm trying to remember what semiconductors I used. But, IIRC, > 2N3055's *were* available around that time. Yup - Quad were using them in the 'late '60s in the 303. -- *Be more or less specific * Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound.
From: Bob Eld on 8 Aug 2006 19:24 "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote in message news:41thd21ulbp36p97bcg9ca99nmni8vko3r(a)4ax.com... > On Tue, 8 Aug 2006 20:51:44 +0100, John Woodgate > <jmw(a)jmwa.demon.co.uk> wrote: > > >In message <qI-dnR0veMUYQkXZnZ2dnUVZ_radnZ2d(a)insightbb.com>, dated Tue, > >8 Aug 2006, t.hoehler <t.hoehler(a)insightbb.com> writes > > > >>Not really worth the effort, IMHO. However, take a look at All > >>Electronics, Hosfelt Electronics, MCM Electronics. > > > >A bit difficult for a person based in UK, perhaps. And 60-0-60 V at > >around 9 A is a BIG receiver or amplifier. Around 300 W/channel. > > Sounds about right. > > Years ago I had a neighbor kid who needed tutoring in Algebra. > > I couldn't get him really interested until I sweetened the pie by > offering to help him build a 400W guitar amplifier IF he got an "A" in > Algebra. > > He did get the "A". > > We built this beautiful thing (in 1975) that was so heavy that it took > two people to carry it, and I had to use fans on the heat-sinks ;-) > > Put out 400W RMS into 4 x 16 ohm speakers in parallel. > > For my effort his father, President of Anthony Pools, built me a > swimming pool at a bargain price. > > ...Jim Thompson > -- > | James E.Thompson, P.E. | mens | > | Analog Innovations, Inc. | et | > | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | > | Phoenix, Arizona Voice:(480)460-2350 | | > | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | > | http://www.analog-innovations.com | 1962 | > > I love to cook with wine. Sometimes I even put it in the food. What pray-tell is an RMS Watt? " Put out 400W RMS into 4 x 16 ohm speakers in parallel."
From: Jim Thompson on 8 Aug 2006 19:33 On Tue, 08 Aug 2006 23:24:15 GMT, "Bob Eld" <nsmontassoc(a)yahoo.com> wrote: > >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote in >message news:41thd21ulbp36p97bcg9ca99nmni8vko3r(a)4ax.com... >> On Tue, 8 Aug 2006 20:51:44 +0100, John Woodgate >> <jmw(a)jmwa.demon.co.uk> wrote: >> >> >In message <qI-dnR0veMUYQkXZnZ2dnUVZ_radnZ2d(a)insightbb.com>, dated Tue, >> >8 Aug 2006, t.hoehler <t.hoehler(a)insightbb.com> writes >> > >> >>Not really worth the effort, IMHO. However, take a look at All >> >>Electronics, Hosfelt Electronics, MCM Electronics. >> > >> >A bit difficult for a person based in UK, perhaps. And 60-0-60 V at >> >around 9 A is a BIG receiver or amplifier. Around 300 W/channel. >> >> Sounds about right. >> >> Years ago I had a neighbor kid who needed tutoring in Algebra. >> >> I couldn't get him really interested until I sweetened the pie by >> offering to help him build a 400W guitar amplifier IF he got an "A" in >> Algebra. >> >> He did get the "A". >> >> We built this beautiful thing (in 1975) that was so heavy that it took >> two people to carry it, and I had to use fans on the heat-sinks ;-) >> >> Put out 400W RMS into 4 x 16 ohm speakers in parallel. >> >> For my effort his father, President of Anthony Pools, built me a >> swimming pool at a bargain price. >> >> ...Jim Thompson > > >What pray-tell is an RMS Watt? >" Put out 400W RMS into 4 x 16 ohm speakers in parallel." > Sine wave into equivalent of 4 ohm load... 4 each 16 ohm speakers in parallel... I think... it was 30 years ago, might have been 4 each 8 ohm speakers... 2 ohm equivalent load. All I remember is the 400W ;-) ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
From: peter on 8 Aug 2006 19:35
Do you need both + and - power at the same time? If not, just have 0-50V would save you half the power. If you need to use 1V at 5A, your power supply would become pretty inefficient (supplying 5W and wasting > 300W). Are you planning to fan cool it? If not you need a huge heat sink. If you use a switching design, it would be a lot more efficient. "Mark Fortune" <mark(a)fortrex.co.uk> wrote in message news:44d8d62e$0$26602$da0feed9(a)news.zen.co.uk... > Greetings to the collective. > > For my next project I want to build a bench power supply and do away with > this old switch mode AT computer PSU that i'm currently using. > > The design I have in mind will be pretty beefy, giving a wide range of > fixed and variable output voltages (i'm thinking from -50v up to +50) and > deliver up to 5amps of current. if my estimates are right i'll need a > 600va+ (100v * 5a + overhead) transformer to do the job well. Now i've had > a look at some transformers in this range, and they're a little out of my > price range. so now i'm considering building my own. > > The specifications I need are as follows: > > primary: 0-230v @ 50Hz > Secondary: 60v-0-60v > secondary output current max: 5A > > I have an intermediate understanding of transformers, but have never > actually built one, hence I am seeking advice from those with experience > in this field. > So where do I start? what type of core is best for this application? - I > have a friend who's blasting off that toroids are best, but i'd like a > second opinion, and what kind of wire to use for the primary and > secondaries? what are good safety practices regarding insulation? Is this > even a feasable project to undertake (moreso on the money side than > timewise). Any other advice also greatly appreciated. |