<s>
A	O
velocity	B-Algorithm
receiver	I-Algorithm
(	O
velocity	B-Algorithm
sensor	I-Algorithm
)	O
is	O
a	O
sensor	O
that	O
responds	O
to	O
velocity	O
rather	O
than	O
absolute	O
position	O
.	O
</s>
<s>
For	O
example	O
,	O
dynamic	O
microphones	O
are	O
velocity	B-Algorithm
receivers	I-Algorithm
.	O
</s>
<s>
Likewise	O
,	O
many	O
electronic	O
keyboards	O
used	O
for	O
music	O
are	O
velocity	O
sensitive	O
,	O
and	O
may	O
be	O
said	O
to	O
possess	O
a	O
velocity	B-Algorithm
receiver	I-Algorithm
in	O
each	O
key	O
.	O
</s>
<s>
There	O
are	O
two	O
types	O
of	O
velocity	B-Algorithm
receivers	I-Algorithm
,	O
moving	O
coil	O
and	O
piezoelectric	O
.	O
</s>
<s>
Piezoelectric	B-Algorithm
sensor	I-Algorithm
velocity	B-Algorithm
receivers	I-Algorithm
are	O
similar	O
to	O
a	O
piezoelectric	O
accelerometer	O
,	O
except	O
that	O
the	O
output	O
of	O
the	O
device	O
is	O
proportional	O
to	O
the	O
velocity	O
of	O
the	O
transducer	O
.	O
</s>
<s>
Unlike	O
the	O
moving	O
coil	O
variety	O
,	O
piezoelectric	B-Algorithm
sensors	I-Algorithm
will	O
likely	O
require	O
an	O
amplifier	O
due	O
to	O
the	O
small	O
generated	O
signal	O
.	O
</s>
