4155A / 4156A / 41501A Semiconductor Parameter Analyzers敘述As a courtesy to customers, on this page you can find PDF versions of some of the technical literature for these products. The 4155A, 4156A, and 41501A were discontinued on January 1, 1998 and became obsolete on January 31, 2003. The 4155C Semiconductor Parameter Analyzer replaces the 4155A, and the 4156C Precision Semiconductor Parameter Analyzer replaces the 4156A. The 41501B SMU and Pulse Generator Expander replaces the 41501A. Please refer to the web pages for these products for more information.Note: Discontinued means that the product is no longer sold, while obsolete means that the product is no longer supported. Keysight Technologies normally supports products for a minimum of 5 years after discontinuance.