The setup above works like a XOR gate (the output will be 1 if exactly one of the inputs is 1). However, the gate marked by a blue box is missing. What is the gate?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
so we need an OR gate