Digital panel meters with VCC < 5V?

[Joerg]

Hell Matt,

Don't laugh too loud, but... Why not stick a AA, C, or D cell in series
with the meter power supply? OK, this is a bad idea if you then have to
regulate the meter supply with a linear regulator, or if this makes the
meter supply too high when the system battery is fully charged. Also, if
there is a general spec of "no batteries or parts that have to be replaced"
then you lose. If it's an LCD meter, though, it probably draws very
little current and a battery may last a long time.

That would be pretty wild. Can't do that. But I have seen it a long time
ago. There was a large tube amp and they must have needed a small bias
voltage at the grid. So, they just placed a battery there. Unless the
amp was over-driven it didn't draw any current from the battery at all.
However, when I opened this amp for repair the cause of all the grief
was that this battery had leaked all over the place. I even had to
re-paint the bottom panel.

This old battery looked cool, with a pouncing lion on there. I wanted to
keep it but it was just too far gone.

Regards, Joerg