On Sun, 8 Nov 2020 15:25:37 -0800 (PST), wrote:

On Sunday, 8 November 2020 13:42:26 UTC, Scott wrote:
My multimeter has a battery test facility that shows the battery as
good or bad (or on the margin). I understand a zinc carbon battery
has a voltage of 1.5 Volts and an alkaline battery has a voltage of
1.2 Volts? How does it know the difference between a very good
alkaline battery and a very bad zinc carbon battery?.

There are 2 requirements for a good battery: voltage & current. Terminal voltage often tells enough, but not always. The other test is to touch probes of a 1A meter to the battery for a fraction of a second, see how fast the needle flies up. Digital meters generally can't do this. Keep the probes on & you'll kill both meter & battery.

Could my battery testing facility (in the multimeter) be doing this?