<s>
The	O
Sharp	B-Device
EL-8	I-Device
,	O
also	O
known	O
as	O
the	O
ELSI-8	O
,	O
was	O
one	O
of	O
the	O
earliest	O
mass-produced	O
hand-held	O
electronic	O
calculators	B-Application
and	O
the	O
first	O
hand-held	O
calculator	B-Application
to	O
be	O
made	O
by	O
Sharp	O
.	O
</s>
<s>
Introduced	O
around	O
the	O
start	O
of	O
1971	O
,	O
it	O
was	O
based	O
on	O
Sharp	O
's	O
preceding	O
QT-8D	B-Device
and	O
QT-8B	B-Device
compact	O
desktop	O
calculators	B-Application
and	O
used	O
the	O
same	O
logic	O
circuits	O
,	O
but	O
it	O
was	O
redesigned	O
to	O
fit	O
in	O
a	O
much	O
smaller	O
case	O
.	O
</s>
<s>
Most	O
electronic	O
calculators	B-Application
before	O
the	O
EL-8	O
were	O
intended	O
for	O
desktop	O
use	O
.	O
</s>
<s>
Sharp	O
's	O
predecessor	O
to	O
the	O
EL-8	O
,	O
the	O
battery-powered	O
QT-8B	B-Device
,	O
was	O
just	O
a	O
portable	O
version	O
of	O
a	O
compact	O
desk	O
calculator	B-Application
.	O
</s>
<s>
Although	O
it	O
was	O
still	O
too	O
bulky	O
to	O
easily	O
fit	O
in	O
a	O
pocket	O
,	O
it	O
was	O
an	O
important	O
step	O
toward	O
the	O
development	O
of	O
the	O
pocket	O
calculator	B-Application
.	O
</s>
<s>
The	O
operation	O
and	O
performance	O
of	O
the	O
EL-8	O
are	O
identical	O
to	O
its	O
predecessor	O
calculators	B-Application
,	O
the	O
QT-8D	B-Device
and	O
QT-8B	B-Device
,	O
because	O
its	O
logic	O
circuits	O
use	O
the	O
same	O
set	O
of	O
four	O
Rockwell-manufactured	O
large-scale	O
integrated	O
circuits	O
.	O
</s>
<s>
The	O
display	O
,	O
like	O
that	O
of	O
the	O
QT-8D	B-Device
,	O
is	O
an	O
8-digit	O
vacuum	B-General_Concept
fluorescent	I-General_Concept
display	I-General_Concept
with	O
nine	O
individual	O
tubes	O
:	O
eight	O
digit	O
tubes	O
and	O
a	O
single	O
extra	O
tube	O
for	O
the	O
minus	O
sign	O
and	O
overflow	O
indicator	O
.	O
</s>
<s>
As	O
with	O
the	O
QT-8D	B-Device
,	O
the	O
tubes	O
are	O
Iseden	O
"	O
itron	O
"	O
tubes	O
with	O
the	O
same	O
distinctive	O
"	O
handwritten	O
"	O
digit	O
style	O
and	O
the	O
same	O
half-height	O
"	O
0	O
"	O
.	O
</s>
<s>
However	O
,	O
unlike	O
the	O
QT-8D	B-Device
,	O
the	O
EL-8	O
digit	O
tubes	O
only	O
have	O
eight	B-General_Concept
segments	I-General_Concept
to	I-General_Concept
form	I-General_Concept
digits	I-General_Concept
,	O
and	O
the	O
EL-8	O
'	O
s	O
extra	O
tube	O
is	O
positioned	O
at	O
the	O
top	O
right	O
corner	O
of	O
the	O
display	O
instead	O
of	O
at	O
its	O
right	O
end	O
.	O
</s>
<s>
Power	O
is	O
supplied	O
by	O
an	O
integrated	O
rechargeable	B-Architecture
battery	I-Architecture
pack	O
or	O
by	O
an	O
external	B-Architecture
battery	I-Architecture
charger	O
,	O
which	O
also	O
serves	O
as	O
an	O
AC	O
adapter	O
to	O
allow	O
the	O
calculator	B-Application
to	O
operate	O
from	O
AC	O
power	O
.	O
</s>
<s>
The	O
battery	B-Algorithm
pack	I-Algorithm
(	O
model	O
EL-84	O
)	O
contains	O
six	O
nickel-cadmium	O
AA	B-Algorithm
batteries	I-Algorithm
connected	O
in	O
series	O
,	O
giving	O
a	O
total	O
voltage	O
of	O
and	O
,	O
with	O
the	O
original	O
batteries	O
,	O
a	O
total	O
capacity	O
of	O
.	O
</s>
<s>
(	O
Present-day	O
nickel-cadmium	O
AA	B-Algorithm
batteries	I-Algorithm
have	O
much	O
greater	O
capacity	O
.	O
)	O
</s>
<s>
The	O
battery	B-Application
charger	I-Application
(	O
model	O
EL-81	O
)	O
supplies	O
power	O
to	O
the	O
calculator	B-Application
's	O
charging	O
input	O
at	O
voltages	O
of	O
;	O
the	O
combined	O
input	O
power	O
rating	O
is	O
about	O
.	O
</s>
<s>
The	O
EL-8	O
'	O
s	O
battery	B-Algorithm
pack	I-Algorithm
is	O
much	O
smaller	O
than	O
that	O
of	O
the	O
QT-8B	B-Device
,	O
and	O
this	O
was	O
critical	O
in	O
reducing	O
the	O
EL-8	O
'	O
s	O
size	O
and	O
weight	O
.	O
</s>
<s>
The	O
QT-8B	B-Device
'	O
s	O
display	O
tubes	O
are	O
driven	O
by	O
discrete	O
transistors	B-Application
;	O
to	O
reduce	O
the	O
number	O
of	O
transistors	B-Application
needed	O
,	O
only	O
one	O
tube	O
is	O
lit	O
at	O
a	O
time	O
,	O
and	O
the	O
circuitry	O
cycles	O
through	O
the	O
tubes	O
in	O
rapid	O
sequence	O
.	O
</s>
<s>
In	O
the	O
EL-8	O
,	O
the	O
display	O
tubes	O
are	O
driven	O
by	O
integrated	O
circuits	O
containing	O
multiple	O
transistors	B-Application
,	O
and	O
all	O
of	O
the	O
tubes	O
are	O
kept	O
lit	O
constantly	O
.	O
</s>
<s>
Furthermore	O
,	O
because	O
each	O
tube	O
in	O
the	O
QT-8B	B-Device
is	O
only	O
lit	O
for	O
a	O
fraction	O
of	O
the	O
time	O
,	O
the	O
tubes	O
need	O
a	O
high	O
momentary	O
brightness	O
in	O
order	O
to	O
get	O
a	O
reasonable	O
average	O
brightness	O
,	O
so	O
they	O
must	O
be	O
driven	O
with	O
a	O
high	O
voltage	O
,	O
requiring	O
a	O
separate	O
high-voltage	O
power	O
supply	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
display	O
improvements	O
,	O
the	O
EL-8	O
also	O
has	O
a	O
more	O
efficient	O
clock	O
generator	O
circuit	O
for	O
its	O
logic	O
than	O
the	O
QT-8B	B-Device
.	O
</s>
<s>
Together	O
,	O
these	O
changes	O
reduced	O
the	O
EL-8	O
'	O
s	O
power	O
usage	O
to	O
less	O
than	O
a	O
third	O
of	O
that	O
of	O
the	O
QT-8B	B-Device
.	O
</s>
<s>
In	O
addition	O
to	O
its	O
own	O
EL-8	O
and	O
EL-8A	O
,	O
Sharp	O
also	O
built	O
OEM	O
versions	O
of	O
the	O
EL-8	O
for	O
the	O
Swedish	O
office	O
machine	O
company	O
Facit	O
and	O
its	O
subsidiary	O
Addo	O
,	O
which	O
sold	O
them	O
as	O
the	O
Facit	B-Device
1111	I-Device
and	O
the	O
Addo-X	B-Device
9364	I-Device
.	O
</s>
