One on my favorite things about binary is its intrinsic property of “if not one then the other”. This basically means anything with two states: true or false, on or off, yes or no, etc. Because of this property you can easily determine the state of a binary system with a single LED. The LED’s on state represents a one and the off state represents a zero. While this is a useful, super-easy way to display information, it does leave something to be desired. I mean, it’s just one LED. I want a binary display that reads as a zero (0) when the attached binary system is in a LOW state and reads as a one (1) when it is in a HIGH state. This can be accomplished using a surprisingly small number of parts. • 5 resistors • 2 NPN transistors • 1 switch (optional) Using the schematic suppied you can wire up a three sets of LEDs that will form either a [1] of a [0].