hi gang this is a piezoelectric speaker
I got from a microwave oven and modified
for use with my crystal radio people
often asked me where to get crystal
earpieces for listening to their crystal
radios well this is probably our
cheapest source microwave ovens are a
treasure trove of parts to do to take
the cover off and then this section
right here on this side I'll find all
sorts of things right over here what I'm
interested in right now is that black
thing right there which contains a
piezoelectric crystal speaker yeah there
you can see the speaker that's the
crystal right there at disk next to the
solver from the board okay so I got my
voltmeter I'll put it on the 2,000
millivolt scale so basically two Holt's
will hook up one end to the alligator
clip to one of the meter probes the
other alligator clip to the other meter
probes and then I'll connect them to the
crystal it doesn't matter which way you
connect things in this case and then
I'll tap the crystal right there that
was 768 millivolts 291 millivolt so
let's go on a 20 volt scale the sign
will vary this meter is on the DC volts
scale is not very good at picking up the
spikes so it's only going to see a part
of what's going on but you can
definitely tell something's going on it
says works okay so I just try it and it
works great so I'll show you what I did
I take one alligator clip connect to the
output of the diode make the other end
to either end of the crystal picked
another alligator clip to ground pick
the other end to the other end of the
crystal and I'll just give it a listen
here I still have it I'll put it in the
speaker might and the microphones the
camera you may not hear
I don't know if you heard that but what
I need to do is put a tube right here to
help direct the sound the end is also
exposed so I'm wondering if maybe a
solid piece of plastic there might help
too okay so I got an old pin right here
and I'm just gonna cut off last I don't
know three quarters of an inch or so and
then I'll hot glue it right over that
hole centered over that hole in the case
okay I've cut a piece of hard plastic
they kind of get from hobby shops use
whatever you have us just want something
hard so that it can capture the sound
energy in the back here and keep it
inside it so I'm just gonna hot glue
that there before I stick that in my ear
I have some rubbing alcohol here which I
want to sanitize the end of this a bit
there you go there's the end result I
was tuned in to something oh yeah loud
and clear I'll put it in the camera
microphone so hopefully you can hear it
too
first great well thanks for watching
check out my youtube channel rimstarorg
for more videos like this that includes
one with step-by-step instructions for
making the crystal radio you saw here
another containing tips and tricks for
crystal radios including more on
earpieces and for variety wondering how
to power a calculator using a solar
panel made out of transistors and thanks
to user Mary L magpie sorry if I
pronounced that incorrectly for this
video response to one of my videos
pointing out that these crystals are
available in microwave ovens and don't
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