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here's the schematic:http://img258.imageshack.us/my.php?image=untitled6ap6.pnginput voltage is 230V
output voltage is 150V
instead of a resistor as a current source, I am using G Pimm's CCS circuit set to output about 78mA.Do I need to heatsink the transistor?
thank you for the help
Follow Ups:
Jarthel,See posts below:
I have a copy of Allens Preamp Cookbook book that you can have a look at before deciding upon whether to spend your hard earned cash - although I highly recommend it.I have also acquired a second copy of 4th edition of (RDH) Radiotron Designers Handbook - yours if you want it (it was given to me for nothing).
Give me a buzz on the weekend (82693539)
If you are talking aboutthe transistor in the shunt reg - work it out - W = V x ABut to know what"A" figure to put in the equation, you need more information than you give:
Like how much shunt current do you want to use? I suggestas much as the signal circuit will draw.
And you sure as hell will need to heatsink the CCS!
Regards, Allen
You will definitely need to heatsink the current source, the heat dissiplation is (230-150)*.078 = 6.24 watts. A TO220 package is only capable of dissipating around 1.5 watts or so without a heatsink, however this is a function of the ambient temperature and allowable temperature rise of the device.I think you are on the right path using a Pimm current source, the LM417 by itself is not capable of the voltage drop, and Allen Wright even suggests to omit the 417 from his MOSFET current source for best sound (replacing with a fixed resistor).
I use the LM317 a lot and I do heat sink it yes..You know everyone playing with CCS or shunt regualtors should pick up a copy of allen wright's tube preamp cookbook.He practically holds your hand all thru it and it has nice schematic circuits and its written so anyone that read and comprehend a bit can understand it.It will answer any questions and its like a an electronics course the way its laid out.
our welcome allen..it is a fabulous book and I love the humorous line in the book to keep the attention of reader and I do that with my automotive students frequently so you can keep their focus so they drift off topic.
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