In einer eMail vom 04.03.99 21:09:08, schreibt Dwight: << Hi If I was to build an electronic visual computer, I would use neon lights. All the logic functions can be done with these and the results are visual. NE2's can be bought in bulk for a few cents each. I built a relay combination lock once but I used relays and doides to cut down on the number of contacts needed. Dwight You need SOME amplifier element; just logic alone would not do. Neon lights for logic certainly would be possible, but neither convenient nor reliable in my mind, since the difference between ignition voltage and burning voltage is not that big. Diodes are MUCH more convenient AND a lot less expensive than Neon lights. John G. Zabolitzky