Holland Membrane, Design Manual

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sense to consider polyester domes if the total dome usage per order is expected to
exceed 2500. A drawback of polyester domes is that they tend to relax and lose their
tactile feel at elevated temperatures and are not recommended for applications that will
experience temperatures above 55
˚ C (131 ˚ F).
Actuation Force
The customer may specify the switch actuation force. Typical actuation forces
range from 6 to 24 ounces. Polyester domes usually have greater actuation force than
do stainless steel domes. Polyester domes have typical actuation forces of 14 to 24
ounces, and stainless steel domes are in the 12 to 18 ounce range. The tolerance on
actuation force is +/- 3 ounces.
Electrical Performance
The great variety of membrane switch designs makes it difficult to outline a
general set of specifications that covers all membrane switches. Listed below are some
basic performance specifications. If an application has specific requirements other than
the ones below, the customer should be certain to communicate them to Holland
Nameplate.
Loop Resistance
The loop resistance of a switch is a function of trace width and length. In almost all
applications the maximum loop resistance is less than 100 Ohms.
Open Circuit Resistance
50 MegaOhms minimum
Contact Rating
100 Milliamps at 28 VDC Maximum
Maximum Load
1.5 VA Nominal
Contact Bounce
5 Milliseconds Nominal
Operating Temperature Range