Selection Criteria
The initial considerations for trimmer type selection are:
A. Resolution of adjustment
B. Setability and time to set
C. Physical and environmental conditions
D. Stability of setting required
E. Circuit packaging requirements

D. Stability of Setting
It is highly desirable that once the trimmer has been set, it should remain at that setting independent of time, operating temperature changes, vibration, shock and humidity. This property of stability is largely a factor of the compatibility of the materials at the moving contact interface and the thermal matching of the elements of the trimmer structure. BI uses noble metals in both the wire brush contact and the cermet element. These materials are relatively soft, highly compatible and provide an excellent, low resistance, non-corroding interface. The contact drive structure and materials are chosen for their stability and compatibility. The high contact forces utilized at the brush/element interface reduce susceptibility to shock and vibration.

The circuit designer can contribute significantly to short term operating and long term stability by mounting the trimmer away from high thermal gradients, hot spots and sources of excessive vibration.

E. Circuit Packaging
BI manufactures trimmers in a variety of package styles and sizes. The chances are excellent that stock models are locally available that will fit your requirements. Models include both pin style and surface mount single and multiturn configurations. Special electrical and mechanical features are available for specific customer applications. Call your local representative or the factory direct for information on special packaging.