Hank102938
New Member
For the LM317k, the junction max temp is 125°C and the junction to case is 2°C/W. So according to audioguru in this post, my input voltage on the higher range will be 33.4V. So, the lowest voltage the higher range would have to cover is 13V or so. 30.6 Watts to be dissipated if current drawn is 1.5A.... so I would need a heat sink with a rating of... um... carry the 4... with a minimum of 1.1°C/W. If I did the LM338k,then the minimum heat sink rating would be 2.1°C/W.. or maybe try the LM138K, 2.9°C/W. But at 13V @ 1A I still would need a 2.6°C/W heat sink using the LM317k... Where can I find a TO-3 1.1°C/W heat sink at the best or a 2.6°C/W one?
So heat aside, what about the filter cap, someone said something about getting one with a larger capacitance? If I do, will my input voltage (the 33.4V @ 25V transformer output or the 15.7V @ 12V center tap) change? And what capacitance should it have?
So heat aside, what about the filter cap, someone said something about getting one with a larger capacitance? If I do, will my input voltage (the 33.4V @ 25V transformer output or the 15.7V @ 12V center tap) change? And what capacitance should it have?
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