From AMS Glossary
(Redirected from Barometric switch)
(Also called barometric switch.) A pressure-operated switching device used in a radiosonde.
In operation, the expansion of an aneroid capsule causes an electrical contact to scan a radiosonde commutator composed of conductors separated by insulators. Each switching operation corresponds to a particular pressure level. The contact of an insulator or a conductor determines whether temperature, humidity, or reference signal will be transmitted.