An instructional aid for digital computer logic

A design is presented of a self-contained instructional aid with which the function of basic digital computing elements may be demonstrated, and in which the elements may be combined to demonstrate the more complex circuits which are part of all digital computers. The speed of operation, and the ease with which elements may be interchanged, combine to make the device particularly suitable for instructional purposes, and the apparatus may also be used for computing experiments. Diodes are used to perform most of the logical functions, with transistors to switch indicating lamps and regenerate digits. Serial operation is used and the machine can be switched to operate at approximately 1000 bits per second, one bit in two seconds, or one bit at a time, i.e. at step-by-step.