Vishay Intertechnology announced a trimmer webinar to help engineers understand the advantages of using precision Bulk Metal Foil resistors and trimmers in applications. In addition to the webcast, Vishay also has a three-minute video that compares the stability of different trimmer technologies when subjected to mechanical shock and vibration. The demonstration shows that while mechanical shock and vibration will cause most trimmers to drift over time, Vishay’s Bulk Metal Foil trimmers have a life stability that can rival fixed resistors.
Vishay’s trimmer webinar highlights the differences in trimmer technologies, with a focus on high-precision applications. A trimming potentiometer is a mechanically driven variable resistor used to trim resistance in an initial circuit, or to adjust this circuit for drift characteristics after load life, shock, thermal shock, or some other circuit-changing experience.
When used as a variable resistor, a trimmer is called a rheostat. When used as an adjustable voltage device, it is called a potentiometer. These devices can be used in general-purpose, non-critical applications, as well as in precision applications; the end application determines which type of trimmer is most appropriate.
There are four categories of characteristics that are generally considered when selecting a trimmer: mechanical, electrical, operational, and economic. While some of these categories may be interrelated, it is generally the operational characteristics which are of paramount concern, and are also the most elusive in high-precision applications. Vishay’s online seminar concentrates primarily on operational characteristics and, to some extent, the technological factors which affect them.
Resistors and trimmers utilizing different technologies often seem alike on the surface, and may even have similar published specifications, such as initial TCR and tolerance. However, the resistive material and processing methods for each are unique. These inherent resistive material, design, and processing variations strongly influence electrical performance, leading to different behaviors after mounting. For example, the stability of a resistor or trimmer should be judged by its performance under load and temperature in short-term and long-term exposure to different electrical or mechanical parameters.
More info: Vishay Trimmer Videos and Webinar