B&K Precision 391B – True RMS Digital Multimeter

• DCV, ACV, AC+DC, DCI, ACI, resistance, capacitance, frequency, diode, temperature, and continuity measurement functions
• True RMS AC and AC+DC measurements
• 40,000-count, dual display
• This version does not have Bluetooth or LoZ
• CAT III 1000 V / CAT IV 600 V protection

The 390B Series True RMS multimeters offer a comprehensive solution for general purpose measurement applications. Bundled with a complete set of accessories, these multimeters provide technicians and engineers with accurate results, data logging capabilities, and measurement features for evaluating a variety of electronics or electrical systems.

BK offers several models in its 390B multimeter series. The chart below provides an overview of each:

PC software can log measurement data at specified intervals with date and time stamps. Log up to 100,000 data points in graph or table format. Measurement data recorded in the field can be exported using the software for analysis.

This easy-to-read display features an analog style bar graph to help identify measurement trends or fluctuating signals. When working in low-light environments, the auto on/off backlight adjusts for best visibility while maximizing battery life.

Dual line display capabilities enable two measurements or one measurement and a math function to appear on screen simultaneously.

The 390B series is equipped with an AC LPF (low-pass filter) to help reduce unwanted electronic noise when measuring AC voltage or AC frequency. The LPF can improve measurement performance on composite sine waves that are typically generated by inverters and variable frequency drives.

Set up the multimeter to measure AC voltage. Press the HFR button to enable the LPF. The multimeter will continue measuring in the chosen AC mode, but now the signal diverts through a filter that blocks voltages above 800 Hz.