Cmos logic Probe Circuit Diagram

This is a Digital Complementary metal–oxide–semiconductor (CMOS) logic Probe Circuit Diagram.The logic probe can indicate four input states, as follows: floating input—all LEDs off logic 0 input— D2 switched on (D3 will briefly flash on); logic 1 input— Dl_ switched on; pulsing input—D3 switched on, or pulsing in the case of a low frequency input signal (one or both of the other indicators will switch on, showing if one input state predominates).

Cmos logic Probe Circuit Diagram