DIYbanter - View Single Post

Phil Hobbs

Lostgallifreyan wrote:
(Hal Murray) wrote in
news
There is another dimension to consider: duty cycle. I've been told
(but don't have first hand experience) that old fashioned carbon
composition resistors are much better at pulse loads that newer
carbon film resistors.

They're also a lot better at high voltage. I'm just mentioning this because
when I used some for a HeNe supply current limit resistor, they really
impressed me. Most other things I tried eventually burned. Basically, a solid
mass is better than a film for HV, it seems.

Except for the horrible voltage coefficient. Carbon comps' resistances
decrease by about a quarter at their rated voltage. That's okay for a
HeNe, since the tube's load line is pretty steep.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net