<s>
In	O
electronics	O
,	O
TO-3	O
is	O
a	O
designation	O
for	O
a	O
standardized	O
metal	O
semiconductor	B-Algorithm
package	I-Algorithm
used	O
for	O
power	O
semiconductors	O
,	O
including	O
transistors	B-Application
,	O
silicon	O
controlled	O
rectifiers	O
,	O
and	O
,	O
integrated	O
circuits	O
.	O
</s>
<s>
TO	O
stands	O
for	O
"	O
Transistor	B-Application
Outline	O
"	O
and	O
relates	O
to	O
a	O
series	O
of	O
technical	O
drawings	O
produced	O
by	O
JEDEC	O
.	O
</s>
<s>
The	O
first	O
use	O
of	O
this	O
design	O
was	O
for	O
the	O
germanium	O
alloy-junction	O
power	O
transistor	B-Application
2N176	O
–	O
the	O
first	O
power	O
transistor	B-Application
to	O
be	O
put	O
into	O
quantity	O
production	O
.	O
</s>
<s>
The	O
metal	O
case	O
forms	O
the	O
third	O
connection	O
(	O
in	O
the	O
case	O
of	O
a	O
bipolar	O
junction	O
transistor	B-Application
this	O
is	O
typically	O
the	O
collector	O
)	O
.	O
</s>
<s>
TO-204	B-Algorithm
is	O
intended	O
to	O
replace	O
previous	O
definitions	O
of	O
flange-mounted	O
packages	O
with	O
a	O
pin	O
spacing	O
.	O
</s>
<s>
The	O
different	O
outlines	O
are	O
now	O
defined	O
as	O
variants	O
of	O
TO-204	B-Algorithm
:	O
TO-3	O
is	O
renamed	O
to	O
TO-204-AA	O
,	O
TO-41	O
to	O
TO-204-AB	O
.	O
</s>
<s>
A	O
new	O
package	O
with	O
a	O
reduced	O
maximum	O
height	O
of	O
is	O
added	O
as	O
TO-204-AC	O
.	O
</s>
<s>
Two	O
additional	O
variants	O
specify	O
pins	O
thicker	O
than	O
the	O
original	O
to	O
allow	O
higher	O
currents	O
:	O
for	O
TO-204-AD	O
and	O
for	O
TO-204-AE	O
.	O
</s>
<s>
Common	O
transistors	B-Application
:	O
</s>
