Artifact Details


ERMETH logic module

Catalog Number



Physical object


ca. 1956


ETH, Zurich

Place Manufactured


Identifying Numbers

Model number EMRETH
Other number E90CC Printed on vacuum tube
Other number N/A
Serial number 286 Scratched on base


overall: 1 3/4 in x 2 1/2 in x 7 1/2 in


"Number ""286"" is hand scribed on connector end of module. Exterior of module contains one vauum tube (Phillips E90CC) and a neon bulb. 20-pin (2 x 10) connector. Module cover held on with two screws, partially backed-out at time of donation. EMRETH stands for Elektronische Rechenmaschine an der ETH, or "Electronic Computer at the Swiss Federal Institute of Technology. The machine was completed in 1956, it operated with 2,000 tubes (double triodes) and 600 semiconductor diodes. (Transistors were not available at the time). The memory was a magnetic drum which stored 10,000 words. The pulse frequency was 100kHz, the computer's speed was about 60 operations per second. The machine had 2,000 pluggable units, wach with 0, 1, or 2 vacuum tubes. The unit on display is a flip-flop, in other words, an electronic bistable circuit. The tube is a double triode E90CC. A neon bulb is provided to indicate the state of the flip-flop, as an aid to troubleshooting; in normal operation, the bulb is not needed. Inside the unit there are indcutors, two pulse transformers, four semiconductor diodes, nine resistors, and two capacitors. Ambrose Speiser Sonnhalde 9 CH-5400 Baden Swizerland August 29,2001


Component: circuit board / module


Gift of Ambros Speiser

Lot Number