The Caltronic 812 is an early portable electronic calculator from the 1970s. With its substantial size and weight, luxurious accessories, and high price, it was positioned as a premium product.
The calculator has an imposing black plastic case with brushed aluminum trim. The design features a deeply recessed red LED display under a convex magnifying filter. An integrated Texas Instruments keyboard assembly provides a loud click feedback. Power comes from a single 9V battery or AC adapter.
Introduced around 1972-1973, the 812 has limited functionality compared to later models. It can perform four basic arithmetic operations in a semi-reverse Polish notation system. The logic allows entry of up to 12 digits but the display only shows 8 digits plus a sign. There is no constant function or flexible decimal setting. Overflow and divide-by-zero errors often freeze the device.
Inside, the calculator exhibits hallmarks of early 1970s electronics. A large white ceramic central processing unit is surrounded by discrete transistors and diodes soldered to a double-sided circuit board. Gold plated contacts connect to the display and keyboard. The complexity of the design suitably matches the premium price tag.
The 812 came in a velvet-lined leatherette case with metal Caltronic logo. No expense was spared to convey luxury and justify the cost. However, the imperfect logic shows the limitations of the era. Within a few years, simplified all-integrated circuit designs and improved programming would vastly increase capabilities while shrinking the form factor. The 812 represents an early milestone in bringing complex electronic calculators from laboratories to the mass consumer market.
