Ma Ku- Papers

Precision Current Measurement A Major Qualifying Project Submitted to the Faculty of Worcester Polytechnic Institute In partial fulfillment of the requirements for the Degree of Bachelor of Science By __________________________ Andrew Houde click here to download file
1 Abstract ABSTRACT: Current measurement is presently possible through a number of different techniques, including resistive sensing, current transformers, and magnetoresistive sensing. The measurement of current using Hall-effect sensors is possible, but not with high precision over a large temperature range. Through laboratory experimentation and research, this project details the characterization of a Hall-effect sensor and provides current measurement results over a range of -6A to 6A that are accurate within 1% over a temperature range of -25 degrees C to +85 degrees C. In this precision current measurement device, the Hall-effect sensor senses the magnetic field produced by a current flowing through a wire. Using equations programmed into PIC assembly microprocessor code, the output of this sensor is then converted into a current value. If the ambient temperature is other than 25 degrees C, the microprocessor also compensates for the effect of temperature on the sensor in its calculations. The designed device, as tested, meets all of the initially established specifications and goals.
Interrupts on PIC micro   Vasile Surducan click here to download file
If u are becoming a PIC-microcontroller user and all new things are puzzling you, starting with interrupts would be "the hell thing" because you'll have to manage with your own imagination all PIC resource, to got the final goal, a functional and stabile circuit board. Usually................................................................................................
Low temperature data remanence in static RAM Sergei Skorobogatov June 2002 15 JJ Thomson Avenue Cambridge CB3 0FD United Kingdom phone +44 1223 763500 http://www.cl.cam.ac.uk/ click here to download file
Abstract Security processors typically store secret key material in static RAM, from which power is removed if the device is tampered with. It is commonly believed that, at temperatures below −20°C, the contents of SRAM can be ‘frozen’; therefore, many devices treat temperatures below this threshold as tampering events. We have done some experiments to establish the temperature dependency of data retention time in modern SRAM devices. Our experiments show that the conventional wisdom no longer holds.