Hi, thanks for this. On the cheap multimeters which I like to play around with like the DT830 it comes in multiple flavors. The b model is basic, then there is one that will measure temperature, then one modle will output a simple sign wave. Some have say it has a buzzer, but it doesn't. The cob is probabily the same for all of them.
How does the designer think when he lays out the pcb. Does he say "We want the b model to work by just putting in this piezo electric element, and not changing anything else, and design it to have a parallel trace or does he include a zero ohm resistor across the leads where the buzzer should connect? Is there a standard way to look at these thing? Or maybe a "best practices" way to circuit design for optional or alternative circuit board uses?