FS9922-DMM4 is a high performance, low power consumption and 3 6/7 digits (6000 Counts) dual Analog to Digital Converter with a built-in microprocessor. It includes a 8 bits microprocessor, low noise and the OPAMP of high stability, AC rectifier OPAMP, voltage doubling and regulated voltage, highly regulated bandgap, auto measurement switch and function control circuit, buzzer driver circuit, clock oscillation circuit, backlight display control circuit, LCD driver circuit and so on. Built-in dual Analog to Digital Converter , one is a high accuracy ADC for main measurement; the other is a high speed ADC whose measurement result shows by a 61 segment analog section bar that can respond fast, the analog indication owns the property of immediate response and can provide the fast measurement and monitoring of instant signals. With the microprocessor, FS9922-DMM4 can do the logic function control via the I/O ports. By selecting the codes of MEA1〜MEA5 pins can realize various functions during measurement. By triggering the keys of the settings of SELECT, RANGE, REL/RS232, HZ/DUTY, HOLD/LIGHT, MAX/MIN keys, you can realize the functions of function switch, measurement mode select, relative value measurement, frequency/duty cycle measurement, reading hold, MAX/MIN value hold, backlight display, RS232 output and so on.