OR Gate
The AND Gate and Or Gate chips are by far the simplest chips in the entire collection. Neither consists of a single transistor and is simply using Diode logic with pull resistors to build the logic gates. This was a fairly common design on vacuum tube computers, particularly as semiconductor diodes became more ubiquitous. It is an elegant and affordable way of creating discrete logic gates.
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This schematic was reverse engineered by tracing out each individual line on the board itself. We are fairly confident it is mostly correct, but there could be errors still present.
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There is some confusion as to what is considered a logic low versus logic high. The manual contradicts itself in a couple of places, and the design of the cards here implies that -3.5V is logic high and 0V is logic low and the computer utilizes negative logic. However, is the design shown in the manual for diode logic AND and OR gates.
