Elias knew the 7106 (or its cousin, the 7107) was a legend. It was an Intersil ICL7106, a chip that contained an entire world: an oscillator, a reference voltage source, and a 3.5-digit analog-to-digital converter (ADC).
The diagram was a map of trade-offs. The designers had stripped away every luxury—auto-ranging, true-RMS, robust fuses—to create something that did one thing perfectly: It gave the common man the power to see electricity. dt830d digital multimeter circuit diagram
The ICL7106 is a 40-pin DIP chip that directly drives a liquid crystal display (LCD) without needing external decoders or drivers. It operates on a single 9V supply but internally generates a 3V reference for the LCD backplane. Its operation is based on dual-slope integration: Elias knew the 7106 (or its cousin, the 7107) was a legend
On the diagram, the path was clear: The voltage enters the (a string of precision resistors), gets stepped down to a safe level the chip can handle, enters the Integrator (Pins 27-29) which turns the voltage into a time-signal, and finally drives the LCD Driver pins. Its operation is based on dual-slope integration: On