<s>
Parametron	B-Device
is	O
a	O
logic	O
circuit	O
element	O
invented	O
by	O
Eiichi	O
Goto	O
in	O
1954	O
.	O
</s>
<s>
The	O
parametron	B-Device
is	O
essentially	O
a	O
resonant	O
circuit	O
with	O
a	O
nonlinear	O
reactive	O
element	O
which	O
oscillates	O
at	O
half	O
the	O
driving	O
frequency	O
.	O
</s>
<s>
Parametrons	B-Device
were	O
used	O
in	O
early	O
Japanese	O
computers	O
from	O
1954	O
through	O
the	O
early	O
1960s	O
.	O
</s>
<s>
A	O
prototype	O
parametron-based	O
computer	O
,	O
the	O
PC-1	B-Device
,	O
was	O
built	O
at	O
the	O
University	O
of	O
Tokyo	O
in	O
1958	O
.	O
</s>
<s>
Parametrons	B-Device
were	O
used	O
in	O
early	O
Japanese	O
computers	O
due	O
to	O
being	O
reliable	O
and	O
inexpensive	O
but	O
were	O
ultimately	O
surpassed	O
by	O
transistors	B-Application
due	O
to	O
differences	O
in	O
speed	O
.	O
</s>
