News and New Products

Tiny reed switch is hard to see, easy to use

By Bill Schweber -- EDN, 3/4/2004

Bell Labs and Western Electric matured and mass-produced the venerable reed switch for use in AT&T central-office switching. It may have lost that role, but designers of specialty applications still prefer it for its extraordinary reliability and hermetic sealing, which keeps dirt and corrosives out and arcing in. Hermetic Switch claims that its HSR-0025 reed switch, which is half the size of its HSR-003 predecessor, is the smallest in the industry. Measuring 4.06×1.22×0.89 mm, this switch works in internally fitted medical devices, medical instrumentation, aerospace, and industrial applications (Picture).

The switch leads measure just 0.25 mm in diameter, contributing to the extreme sensitivity of the switch; it requires two to 15 ATs (ampere-turns) to activate, depending on the version. Its Form A contacts handle 30V ac/dc, 0.01 A, and 0.25W maximum power. Prices range from $1.65 to $3.10 (1000).

Hermetic Switch Inc, 1-405-224-4046, www.hermeticswitch.com.