Quality bridges are used in labs all of the time. The manual ones
are in laboratories for experiments, but the electrical and electronic
ones measure R-C-L components in various combinations. Often the AC
speaks of the ability for the C-L or reactive bridge branches.
Martin
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Life; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/
DT wrote:
1114 - I don't thnk this is a simple wheatstone bridge. Wheatstone bridges
work on DC. This has crude switches labeled D.C. / A.C. that are ganged
together, and a switch that selects between TEL / GAL. It may be an early
form of a multi-function meter. It may be a conductivity bridge which can
use either DC or AC as excitement. The TEL/GAL switch is interesting. GAL
may represent galvanometer - a type of ammeter. The wikipedia article for
galvanometer (http://en.wikipedia.org/wiki/Galvanometer) also states that
they were used as a receiver for telegraph systems. This may be what the
TEL represents. Might this be a test set of some sort for troubleshooting
telegraph systems? It could also be a test set for checking telephone
lines as the date 1918 (8/13/18 date on warranty sticker) would place it in
the early days of commercial telephony.
A.C. wheatstone bridges use sound instead of a needle deflection. When they are
nulled, there is no sound from the headphone.
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