The Pickering Series 108 is a range of magnetically screened single-in-line reed relays that stack on 0.15 inches (3.8mm) pitch, resulting in a 25 percent saving in board space over 0.2 inch (5.08mm) wide relays.
This means that it is possible to pack 33 percent more relays into the same board area.
Their small size, superb contact resistance stability and ultra high insulation resistance, greater than 10¹² ohms for Form A devices, make these relays a popular choice for high quality instrumentation.
The device is encapsulated in a mu-metal can using a very high resistivity resin. Mu-metal is used rather than steel because of both its very high permeability and its low magnetic remanence. This construction totally eliminates the risk of magnetic interaction problems. Magnetic interaction is usually measured as a percentage increase in the voltage required to operate a relay when two additional relays, stacked one each side, are themselves operated. An unscreened device mounted on this pitch would have an
interaction figure of around 40 percent, it would therefore be totally unsuitable for applications where relays are to be packed densely. Pickering Series 108 have a typical interaction figure of only 1 percent.
Dry switches are available in 1 or 2 Form A (energize to make) and 1 Form C (change-over) configurations. 3, 5 and 12 Volt coils are available, 5 Volt coils have a resistance of 500 Ohms and may therefore be driven directly from TTL logic.