Hi arcom,
As you have come back on this,
maybe you actually want to make it.
I dont know what 'M' is, maybe an electrostatic LS ?
The chances of you having one knocking about are slim.
I would suggest an old earpiece, one of those magnetic
diaphragm ones, even one of those tiny little new ones
might do at those frequencies.
I dont like the way 'M' is strung across the two
collectors, i would put a cap in series with it,
that would not affect its function at all.
(0.1 mfd ?)
First off, a small box.
I tend to build everything on the lid,
it makes things easier to work on.
Mount the switch, battery, and earpiece.
That frequency is audible although at the top end of
most peoples hearing, so i wouldnt bother with a lamp
which would probably drain the battery quicker than
the oscillator anyway.
It doesn't need to be loud, so you're aiming at low
current from the battery, i would suggest around 7k
in the collectors, for small npn TRs like 108 or
similar. Base resistors, hard to say, i would guess
at between 100k to 1M, you'll have to fiddle about.
The capacitors, again, they depend on the other bits
i would guess at about 0.005 mfd to start, increase
a bit to reduce frequency, decrease a bit to raise.
I think the frequency is actually quite critical to
do the job.
Again, i had thought these things were to attract
mosquitoes, not to repel them, but kinjalgp says he
has used them.
He also says they are useless.
Maybe the frequency has to be 'tuned' to the local
mosquitoes.
Maybe its job is to attract them,
and you have to position it carefully,
so it would divert them from the window or door.
Maybe it is for indoor use, to attract them to a
trap or to an 'insecticutor'
I am not convinced it will repel them.
Best of luck with it,
John