DATAMATH CALCULATOR MUSEUM
Texas Instruments SR-22
|Date of introduction:||Sept.11, 1973||Display technology:||Panaplex II|
|New price:||$350||Display size:||10+2|
|Size:|| 9.1" x 6.5" x 2.6"
232 x 165 x 67 mm3
|Weight:||31.0 ounces, 881 grams||Serial No:||5601|
|Batteries:||BP-200||Date of manufacture:||year 1974|
|AC-Adapter:||AC9222||Origin of manufacture:||USA|
|Precision:||13||Integrated circuits:||TMS0207, TMC0323, TMC0404|
|Program steps:||Courtesy of:||Joerg Woerner|
|Download manual:||(US: 1.8 MByte)|
Look carefully at the display of the SR-22 and you'll notice immediately that this calculator could perform amazing calculations. It is the only calculator reported so far to perform Octal-Decimal-Hexadecimal conversions on the base of floating point numbers. Later calculators like the TI Programmer work only on integer numbers.
The SR-22 is one of the few scientific desktop calculators manufactured by Texas Instruments. It uses a housing with the size of a TI-3500 but the extreme wedge shape of the SR-10.
Dismantling this SR-22 manufactured early in 1975 reveals a very rigid construction based on one rather complex printed circuit board (PCB) with two satellites:
|• The Panaplex II display
manufactured by Burroughs.
• The keyboard assembly with the keys, slider switch and discrete LED's.
The Main-PCB itself consists of four major building blocks:
|• Upper part||Discrete high-voltage drivers for the Panaplex II display.|
|• Middle-left||Clock circuit|
|• Lower-left||Voltage supply|
|• Middle-right||Calculating circuit|
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© Joerg Woerner, December 5, 2001. No reprints without written permission.