Electronics/Strange circuit diagram
I'm studying digital circuits and I have one question about the circuit diagram representing an AND operation using diodes.
Above is the circuit of this operation. The problem is that this circuit doesn't have a ground and Z is measuring voltage, but in only one wire! If X and Y are connected to a voltage supply of 5V Z is equal to 5V. So I would like to know what terminals Z are measuring to have a output of 5V.
The diagram you sent comes from this page:
An explanation of and gates is included which you can read through.
The diagram is just for concept of what takes place when the diodes are activated. It is assumed the voltages are referenced to neutral or ground zero. And as most gates are driven with a positive voltage and negative voltage source it could be a phantom ground but either way the purpose of the simple diagram is not to be technically accurate but to show the AND functionality.
I think the explanation of the web page are adequate for your understanding but let me know if it needs more elucidation.