Telrad Dew Heater

great stuff. thanks DaveL

Cheers Donal, thanks for the info.

I had the diodes handy already so I used them, you could use a small regulator instead, it would take less space also.

Well that's one way to use up all those spare diodes I have lying around in my electronics box! ...or as you say, you could build a voltage regulator:

ochra.110mb.com/Home%20Page/Astronomy%20...ter/Variable-PSU.htm

You could more or less directly substitute a 3v regulator chip for the LM317.

Phil.