TRADIC, completed in January 1954, which used a single high-power output vacuum-tube amplifier to supply its 1-MHz clock power.

The first fully transistorized computer was either the Harwell CADET, which first operated in February 1955, although the price paid for this was that it operated only at the slow speed of 58 kHz, or the prototype IBM 604 transistor calculator. The Burroughs Corporation