Are there "inverted relays"?
My answer to SE EE question Are there "inverted relays"? This story is another very recent example of how the questions asked in SE EE awaken my creative activity. Thanks to the experience I have from electronic circuits, I was able to explain in a new (for me) way how the operation of the humble electromechanical relay can be reversed. My answer Short answer: A relay can be "inverted" by "inverting" either the coil (connecting to Vcc) or contacts (make them NC). Structure. A relay consists of two cascaded parts (stages) - an input part (coil) and an output part (contacts). They can be considered as a kind of "converters" with input and output: the coil converts the input voltage into a magnetic field and armature movement; the contacts convert the armature movement into a resistance (on/off circuit). Each of them can be "noninverting" and "inverting" so that a total of four combinations are possible. To make an "inve...