Indicator for Logic of Tri-State Driver
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2005-Feb-16
This article describes a method of visually indicating which state a tri-state logic output driver is in. Although it is fairly easy to determine when a driver is in either the high or low state, determination of when it is in the high impedance state is difficult. In addition, without the use of an oscilloscope, it is difficult to determine if pulses are present at the output. A pair of LEDs (light emitting diodes) along with a pair of resistors can be used to easily indicate all four states (high, low, high impedance and pulses).