<s>
A	O
scratch	B-Algorithm
drive	I-Algorithm
actuator	I-Algorithm
(	O
SDA	O
)	O
is	O
a	O
microelectromechanical	B-Architecture
system	I-Architecture
device	O
that	O
converts	O
electrical	O
energy	O
into	O
one-dimensional	O
motion	O
.	O
</s>
<s>
The	O
actuator	B-Algorithm
component	O
can	O
come	O
in	O
many	O
shapes	O
and	O
sizes	O
,	O
depending	O
on	O
the	O
fabrication	O
method	O
used	O
.	O
</s>
<s>
The	O
actuator	B-Algorithm
sits	O
on	O
top	O
of	O
a	O
substrate	O
that	O
has	O
a	O
thin	O
insulating	O
dielectric	O
layer	O
on	O
top	O
.	O
</s>
<s>
A	O
voltage	O
is	O
applied	O
between	O
the	O
actuator	B-Algorithm
and	O
the	O
substrate	O
,	O
and	O
the	O
resulting	O
potential	O
pulls	O
the	O
body	O
of	O
the	O
actuator	B-Algorithm
downwards	O
.	O
</s>
<s>
When	O
this	O
occurs	O
,	O
the	O
brush	O
is	O
pushed	O
forwards	O
by	O
a	O
small	O
amount	O
,	O
and	O
energy	O
is	O
stored	O
in	O
the	O
strained	O
actuator	B-Algorithm
.	O
</s>
<s>
When	O
the	O
voltage	O
is	O
removed	O
,	O
the	O
actuator	B-Algorithm
springs	O
back	O
into	O
shape	O
while	O
the	O
bushing	O
remains	O
in	O
its	O
new	O
position	O
.	O
</s>
<s>
The	O
voltage	O
is	O
usually	O
applied	O
to	O
the	O
actuator	B-Algorithm
by	O
means	O
of	O
a	O
'	O
tether	O
 '	O
.	O
</s>
