<s>
The	O
SR-50	O
was	O
Texas	O
Instruments	O
 '	O
first	O
scientific	O
pocket	O
calculator	B-Application
with	O
trigonometric	O
and	O
logarithm	O
functions	O
.	O
</s>
<s>
It	O
enhanced	O
their	O
earlier	O
SR-10	O
and	O
SR-11	O
calculators	B-Application
,	O
introduced	O
in	O
1973	O
,	O
which	O
had	O
featured	O
scientific	O
notation	O
,	O
squares	O
,	O
square	O
root	O
,	O
and	O
reciprocals	O
,	O
but	O
had	O
no	O
trig	O
or	O
log	O
functions	O
,	O
and	O
lacked	O
other	O
features	O
.	O
</s>
<s>
It	O
competed	O
with	O
the	O
Hewlett-Packard	O
HP-35	B-Device
.	O
</s>
<s>
The	O
SR-50	O
had	O
a	O
red	O
LED	O
display	O
with	O
a	O
signed	O
ten-digit	O
mantissa	B-Algorithm
plus	O
a	O
signed	O
two-digit	O
exponent	O
for	O
floating	B-Algorithm
point	I-Algorithm
numbers	I-Algorithm
(	O
negative	O
values	O
were	O
indicated	O
with	O
a	O
leading	O
minus	O
sign	O
and	O
positive	O
values	O
with	O
no	O
sign	O
)	O
.	O
</s>
<s>
Internally	O
,	O
calculations	O
were	O
performed	O
with	O
a	O
13-digit	O
mantissa	B-Algorithm
,	O
providing	O
much	O
greater	O
calculation	O
accuracy	O
than	O
the	O
10-digit	O
precision	O
of	O
most	O
scientific	O
calculators	B-Application
of	O
the	O
time	O
.	O
</s>
<s>
After	O
the	O
leading	O
sign	O
,	O
digits	O
consisted	O
of	O
a	O
seven-segment	B-General_Concept
display	I-General_Concept
plus	O
decimal	O
point	O
.	O
</s>
<s>
Like	O
most	O
scientific	O
calculators	B-Application
,	O
the	O
SR-50	O
mostly	O
used	O
ordinary	O
infix	O
notation	O
,	O
as	O
opposed	O
to	O
the	O
postfix	O
Reverse	O
Polish	O
Notation	O
(	O
RPN	O
)	O
employed	O
by	O
its	O
competitor	O
,	O
the	O
Hewlett	O
Packard	O
HP-35	B-Device
.	O
</s>
<s>
This	O
is	O
because	O
the	O
calculator	B-Application
would	O
execute	O
the	O
log	O
function	O
before	O
performing	O
the	O
multiplication	O
operation	O
,	O
and	O
complete	O
the	O
multiplication	O
operation	O
before	O
executing	O
the	O
addition	O
operation	O
.	O
</s>
<s>
An	O
unusual	O
feature	O
of	O
the	O
SR-50	O
was	O
that	O
its	O
included	O
functions	O
like	O
factorial	O
and	O
hyperbolic	O
trig	O
functions	O
,	O
which	O
were	O
found	O
on	O
very	O
few	O
calculators	B-Application
(	O
including	O
the	O
HP-35	B-Device
and	O
HP-45	B-Device
)	O
at	O
the	O
time	O
.	O
</s>
<s>
The	O
SR-50	O
had	O
very	O
fast	O
trig	O
functions	O
(	O
about	O
half	O
a	O
second	O
to	O
evaluate	O
each	O
function	O
)	O
and	O
was	O
a	O
popular	O
calculator	B-Application
to	O
use	O
in	O
contests	O
involving	O
pocket	O
calculators	B-Application
.	O
</s>
<s>
It	O
was	O
thicker	O
and	O
longer	O
and	O
could	O
perform	O
224	O
program	O
steps	O
recorded	O
on	O
magnetic	O
cards	O
,	O
similar	O
to	O
its	O
competitor	O
HP-65	B-Device
.	O
</s>
<s>
The	O
matte	O
white	O
upper	O
face	O
of	O
the	O
cards	O
could	O
be	O
marked	O
with	O
pen	O
or	O
pencil	O
to	O
indicate	O
the	O
program	O
and	O
the	O
functions	O
assigned	O
to	O
the	O
calculator	B-Application
's	O
programmable	O
keys	O
.	O
</s>
<s>
In	O
1976	O
Texas	O
Instruments	O
released	O
the	O
TI-30	B-Device
budget	O
calculator	B-Application
at	O
one-third	O
the	O
price	O
of	O
the	O
SR-50	O
,	O
so	O
sales	O
of	O
the	O
SR-50	O
quickly	O
dropped	O
.	O
</s>
