1)You would probably be able to get away with not heatsinking it.
Mine is running 9v with 100% duty cycle. Runs hot but no harm so far.
or
2)If you have left a reasonable lead length on the BS170's then
you can use these style heatsinks and just give the BS170's a little
twist and bend over to fit the alternative heatsinks in the link below.
They don't take so much space.
Link sends you to RS.
Hope this helps.
73 de Andy G0FTD
