LED control circuitry information display - consists of parallel circuits of LEDs and bridging transistors coupled in series

摘要

The control circuitry contains parallel connections of at least one light emitting diode (13-19) and a bridging transistor (20-26), which are connected in series. If two light emitting diodes are used, they are series connected and in parallel with a common switching transistor. The series connection of the parallel circuitry may be connected to a voltage source across a resistor which may be so dimensioned that the current through one diode does not exceed a maximum value when a minimum number of the diodes are simultaneously activated. The current lead may form a part of the resistor. Alternately the connection to the voltage source may lead across a constant current circuit (34-37).