Bowmar 901D PCB & Components

The Bowmar 901D Printed Circuit Board (PCB) has Texas Instrument’s TMS 0107 NC calculator chip soldered to it. There is also the 10-digit LED module and the four driver chips mounted to it. If you were an electronics student wondering what the point of a bi-stable circuit was, then here is a good application example. A pair of transistors in a bi-stable configuration generates the digital clock pulse for the calculator chip.

The early calculator chips also required negative voltage rails; hence, a DC-to-DC converter type circuit consisting of a small transformer and a cluster of transistors produce the various voltage rails for the circuit.

Texas Instruments TMS0107

Back in its time, this would have been one of the most powerful chips ever made which could perform all four basic mathematical operations! It even had a very generous Static Random Access Memory (SRAM) storage facility to store one numerical value! I would love to find more information about the chip, and if anyone has any information about it, which he or she could send me, then that would be great!

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