Hans Krobath is an independent consultant with EEC, Nesconset, N.Y. Email address: hkrobath@suffolk.lib.ny.us
4 results found for Hans Krobath, displaying items 1 - 4
November 16, 2006[Ideas For Design] Drive Large 7-Segment LED Displays Using Only 1 Or 2 MCU Pins
Many options exist to drive seven-segment LED displays, but most are limited to low output currents. The approach described here uses one 74ALS374 or 74AS374 octal latch, wired as a shift register, per digit. The 74ALS374/74LS374 can handle an output sink current of 24 mA per bit, and the 74AS374 can handle 48 mA per bit, suiting it for large bright displays. Using this approach, you can not only generate the numbers 0 through 9, but also leading zero suppression,...
February 16, 2006[Ideas For Design] Powerline Dropout Simulator Tests Reset Circuits
Short ac powerline dropouts can cause incomplete power-on resets, leaving the microcontroller and logic circuits in an indeterminate state. This susceptibility can be tested using a very low-cost eight-pin microprocessor and a solidstate relay (SSR). Operation of the reset circuit under test is accomplished by varying the number of half-cycle powerline dropouts. The dropout simulator, an ATtiny11 MCU, detects the line frequency zero crossing using level shifter Q1 and its...
June 9, 2005[Ideas For Design] Sense Small Inductance Changes Over A Wide Range
Small inductance changes on the order of 0.01% can easily be sensed over a wide range with a simple circuit connected to a serial port (see the figure). Using a classic Colpitts oscillator interfaced to an eight-pin Atmel ATtiny12-8 microprocessor, the period of multiple oscillator cycles—which is proportional to the inductance—can be sensed. Applications include metallic proximity sensing and seismic detection....
