>A lamp is ideal for this purpose because of its thermal time constant.
A PTC (or cheaper, a NTC in another connection) can also be used.
/Morgan


/  Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \
\  mrt@iname.com, ph: +46 (0)414 70741; fax +46 (0)414 70331    /