Key Features:
Measurement Functions: DCV, ACV, AC+DC, DCI, ACI, resistance, capacitance, frequency, diode, temperature, and continuity.
True RMS Measurements: AC and AC+DC.
Bluetooth Connectivity (Model 390B only): Monitor live data and log it from a mobile device.
Up to 100,000-count, dual display.
Advanced math functions: dB, dBm, limits, peak-hold, REL (delta), MIN, MAX, and average.
High Frequency Rejection (HFR) Mode: A low pass filter for AC measurements (800 Hz cut-off).
Isolated USB Interface: Operating software included for remote data logging.
Durable Construction: Dirt and water-resistant housing with a rubberized protective case.
CAT III 1000 V / CAT IV 600 V protection for safety in high-voltage environments.
Features Comparison for Different Models:
| Features | 392 & 393 | 391A | 390A | 389A | 388B |
| True RMS | ✓ | ✓ | – | – | – |
| Ranging | Auto/Manual | Manual | Auto/Manual | Auto/Manual | Manual |
| DCV Accuracy | 0.08% | 0.05% | 0.10% | 0.25% | 0.50% |
| AC/DC Voltage and Current | ✓ | ✓ | ✓ | ✓ | ✓ |
| Display Digits, Count | 60,000, 4 5/6 | 20,000, 4 1/2 | 4,000, 3 3/4 | 4,000, 3 3/4 | 4,000, 3 3/4 |
| Bar Graph | ✓ | – | ✓ | ✓ | – |
| Capacitance Measurement | ✓ | – | ✓ | ✓ | ✓ |
| Transistor Test | – | – | – | – | ✓ |
| Temperature Probe | ✓ | – | ✓ | – | – |
| Logic Probe | – | ✓ | – | – | ✓ |
| Relative Mode | ✓ | – | ✓ | ✓ | – |
| Min/Max Hold | ✓ | – | ✓ | ✓ | – |
| Peak Hold | ✓ | – | ✓ | ✓ | – |
| Data Hold | ✓ | ✓ | ✓ | ✓ | – |
| USB Interface | 393 only | – | ✓ | – | – |