[Elecraft] power dissipation in a LM150?

[Lyle Johnson]

Hello Jeff!

> Can someone tell me how to calculate the power dissipation in the
> LM150?

Except for the operating current of the regulator (probably less than 10 mA)
the power dissipated in the regulator is in fact (Vin-Vout)* Current.

> I use a small power supply for a "Gateway 2000 Solo" laptop computer to
> power my K2. It is rated 19V and 2.64A. To drop the voltage down to 14V I
> put a LM150 in a small cast aluminum box. The system works well except the
> regulator box gets very hot during long operating sessions like field day.

I suggest you paint the box a color as close to the now-forbidden "lead
oxide" white as you can.  Aluminum is terrible at radiating heat, though it
conducts it well.  White will radiate heat well - as well as black!  As a
bonus, white reflects light so the sun shining on it won't add to the heat.

73,

Lyle KK7P