A pair of electrical display elements, LEDs, is driven by a three-state buffer driver circuit. The LEDs have associated current-limiting resistors. The driver circuit applies different selected voltage levels at different selected predetermined frequencies to the LEDs. By having two predetermined frequencies...http://www.google.fr/patents/US5666129?utm_source=gb-gplus-shareBrevet US5666129 - Electrical display elements for displaying multiple different conditions
Electrical display elements for displaying multiple different conditions
