Posted by Damir [ 213.202.68.63 ] on February 13, 2005 at 15:15:00:

In Reply to: Re: CCS heatsinks posted by colinhester on February 13, 2005 at 14:45:04:

Easy, "top" mosfet (connected to the B+) drops about all the voltage from B+ to the Ua (anode voltage). It`s about 100V difference, and with 15 mA - P=1,5W, even small heatsink is "good enough" - IMO.
Interesting, in BC55B/MJE350 CCS, the transistor close to the anode load, or "lower" one (MJE350) needs cooling - opposite then DN2540 cascode CCS.

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