I'm wondering if that little dot represents anything?

enter image description here

  • \$\begingroup\$ what is your question? ... you did not ask one \$\endgroup\$ – jsotola Aug 10 at 1:05
  • \$\begingroup\$ The bubble indicates signal inversion because one side of the wire is active-low, and the other side of the wire is active-high. So it is a “free” logical inversion due to the way the input and output signals were defined. The bubble is just a reminder that this is a mixed-logic system, with a logical inversion happening there. \$\endgroup\$ – MarkU Aug 10 at 1:13
  • \$\begingroup\$ Thank you, Makes perfect sense. \$\endgroup\$ – Charles Peckham Aug 10 at 2:07

The dot represents inversion. It's an OR gate with one input inverted.

An equivalent circuit is:


simulate this circuit – Schematic created using CircuitLab

(Imagine the triangle part of the inverter disappearing, and you'll see the resemblance.)

  • \$\begingroup\$ Thank you very much. This makes sense. \$\endgroup\$ – Charles Peckham Aug 10 at 2:07

In the logic symbols, the bubble represents the inversion. Whatever is the signal, the bubble inverts that signal. For example, in the picture AND gate is used. logic gate

The output should be logic 0 but due to bubble at output, the output of gate changed to logic 1.


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