On Thu, 29 Oct 2020 13:57:16 +1100, Chris Jones
wrote:

snip

and it is probably unnecessary after the first charging cycle. The
capacitor won't have time to discharge much when the button is pressed,
which means it won't take long to recharge either.

What sort of leakage do these caps have Chris?

Here is a datasheet. Tens of microamperes or less. I didn't know but
they come in voltage ratings above 5.5V so you would only need one
capacitor:
https://au.mouser.com/datasheet/2/40...CM-1018838.pdf

Interesting, thanks.

Are these the sorts of things they have in these clever capacitive
based vehicle jump starting units?

snip

but it might alter the sound of the existing doorbell when it
releases.

Not if I get the charging resistor right?

True. That's the main advantage I can think of for putting a charging
resistor. There might be an argument for using a zener diode rather than
a rectifier diode in parallel with the charging resistor, as I don't
know whether breakdown might be destructive for a diode not intended as
a zener.

Understood.

snip

I'll have to rig something up and see how it goes (and it's easier to
find 6V buzzers). ;-)

I think you should try it and please report back how it goes.

You should see from elsewhere I'm going to try the low voltage series
buzzer first and yes, of course I'll report back as I can't be the
only one in this position who might appreciate a 'simple' solution?
;-)

Cheers, T i m