The TC820 is a 3-3/4 digit, multi-measurement system especially suited for use in portable instruments. It integrates a dual slope A/D converter, auto-ranging frequency counter and logic probe into a single 44-pin surface mount, or 40-pin through hole package. The TC820 operates from a single 9V input voltage (battery) and features a built-in battery low flag. Function and decimal point selection are accomplished with simple logic inputs designed for direct connection to an external microcontroller or rotary switch.