Standards are established norms or requirements for technical systems in industry. Penn Libraries provides access to standards from these organizations:
Provides access to over 590,000 electrical, mechanical and optical component families. You will need to register (this is free!) to access the product information.
Product information from American manufacturing companies. Access is free, although registration is required to search the database. It is an excellent source for finding out who makes what.
EEM (Electronic Engineers Master) is a compilation of catalogs of electronic components, equipment, and services. Search by product type (transformers, integrated circuits, filters, etc.) or by manufacturer. Product information is taken directly from the manufacturer's or supplier's catalog.
eFunda, or engineering Fundamentals, is a freely accessible website providing reference resources and tools for engineers. Also available are links to (mostly) free trade publications in a variety of industries.