The proposed work is aimed at design, development, testing, and production of improved material components and circuits which can have application in systems for magnetic resonance imaging systems for the purpose of providing superior performance (e.g., particularly, low noise, low loss, broadband class AB pulse amplifiers) at lower initial costs and significantly lower operating costs based on reduction of energy losses. The Phase II work will perform total system integration and prototype manufacturing of 5 KW class AB pulse amplifiers for MRI based on successful Phase I developments of novel 200 W bipolar rf power circuits for broadband operation from 5 MHz to 150 MHz and 12 KW-80 KHz switching power supplies. R&D on improvement of low loss binders for high power carbonyl iron powder transformer cores will continue.