"Cydrome Leader" wrote in message
...
Ian Field wrote:


"Ken Layton" wrote in message
...
On Friday, October 23, 2015 at 9:07:18 PM UTC-7,
wrote:
Cylindrical. Axial leads.

Ordered caps for a speaker crossover because the leads had literally
been
shaken out of the originals. But I had no luck finding those bulbs. I
would rather not jump it out. I guess I could and just put a beefier
horn
in it.

It's called a "barreter". It's just a lamp used as a current limiter.

The earliest reference I could find to baretter was from the pioneering
days
of wireless - apparently it was used as a detector.

The type I remember from the days of AC/DC TVs and radios was an iron
wire
filament enclosed in a hydrogen filled envelope.

What did these tubes look like, any idea why they used iron and hydrogen?

They were long-ish tubes with an octal base. There was a glass stem inside
with radial support spring struts and the wire zig-zagged up and down to
complete a circle inside the tube.

When I got into the trade, they'd been largely superseded by rod type
thermistors, there was just the odd one or two turned up in older gear - as
they never gave me any problem, I never bothered researching it much.

Searching; "C1.pdf" will get you a datasheet, or search; "barretter" will
get you some old radio museum pages for stuff they're used in.