Sharp EL-503

Date of introduction:  1979 Display technology:  LCD
New price:   Display size:  8 (5 + 2)
Size:  5.8" x 2.6" x 0.75"    
Weight:  4.4 ounces Serial No:  
Batteries:  2*AA Date of manufacture:  year 1980
AC-Adapter:  EA-10B Origin of manufacture:  Japan
Precision:  11 Integrated circuits:  TP0327N
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

At first glance this early Sharp EL-503 scientific calculator looks not really exciting. A bulky housing, a very limited keyboard with just 28 keys and a LCD display with only 8 digits ranks the EL-503 even in the 1979/80 timeframe at the lower end of the list. 

EL-503_PCB.jpg (229287 Byte)Dismantling the EL-503, on the other hand, reveals a big surprise: This calculator makes use of a Texas Instruments TP0327 single-chip calculator circuit based on the TMS1000 Microcomputer family. The TP0320 architecture was introduced in 1978 and powered the Slimline calculators family centered around the Texas Instruments TI-50, TI-53, and Business Analyst II.

EL-503_IC.jpg (98981 Byte)Running Mike Sebastian's "Calculator forensics" gives a result of 9.177087103, well-known since the TI-30 introduced in 1976.

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Joerg Woerner, November 3, 2008. No reprints without written permission.