121GW Product Webpage
121GW User's Manual (08.02.2019)
121GW Circuit Diagram
121GW BLE Packet Protocol Format
121GW Latest Firmware
121GW PC Software

121GW Multimeter Fuses

• HV110 11A 30kA 1000V HRC (10x38mm)
• HV620 400mA 10kA 1000V HRC (6x32mm)

• Bluetooth connectivity (multi-device capability)
• Open Source Cross Platform application software (Android + Windows, and more soon)
• 15V Diode Test Voltage (useful for Zeners + LED strings etc)
• VA Power measurement
• Low Burden™ voltage
• Unique burden voltage display
• Micro SD Card data logging + firmware updating
• Other major features include:
• Dual 50,000 count display with bargraph
• 0.05% + 5 Basic DCV Accuracy
• Auto-Hold measurement
• 600V CAT-III with independent UL 61010 certification by ETL
• Safe operation through HRC fuse + TVS + PTC + MOV + Diode Bridge protection
• AD8436 >100KHz True RMS
• 4 x AA battery powered with 500+ hr battery life
• Compact design – 84 × 165 × 59 mm (W × L × H)
• Hackable ST ARM Cortex M3 processor (S-LINK/V2 programmer interface inside)
• Hycon HY3131 chipset
• MAX4238 Low Offset Amplifier for current ranges
• SD Card firmware update
• Full Open Schematic available
• 8ppm ADR3412 voltage reference

The meter is manufactured by UEI Test Instruments, a reputable US based designer and manufacturer of high quality test gear. The design work was primarily done by UEI, but with a great deal of design input and direction from Dave. The meter is manufactured in South Korea.

NOTE: The meter may come with either Brymen (gold) probes or UEI (nickel) probes depending upon availability at the time. Both are high quality silicone rubber probes.