Hewlett Packard HP 9810A programmable desktop calculator, 1971.

This was the second calculator made by Hewlett Packard and was launched as an easy upgrade from its predecesor, the HP 9100. The calculator made use of technological advances, including IC chips for RAM (random-acces memory), ROM (read-only-memory) and logic, as well as a three-line LED (light-emitting diode) display instead of the cathode ray tube (CRT) display used on the HP 9100.