Fluke 8921A True RMS Voltmeter

The Fluke 8921A True RMS Voltmeter delivers precise voltage measurements across a wide frequency spectrum from 10 Hz to 20 MHz. This instrument provides true RMS readings for both sinusoidal and non-sinusoidal AC signals, including those with DC components, making it essential for electronic testing, calibration, and frequency analysis work. With measurement capability from 180 µV to 700 V rms and resolution to 0.05% of range, the 8921A combines laboratory-grade accuracy with portable field-ready design.

– Technical Specifications

Measurement Functions
• AC true RMS
• AC + DC true RMS

Voltage Range: 180 µV to 700 V rms
Frequency Range: 10 Hz to 20 MHz
Resolution: 0.05% of range; 0.1 µV minimum on lowest range
Crest Factor: Seven at full scale
Input Impedance: 10 MΩ

Display Options
• Volts (3½ digit)
• dB (4½ digit) with 12 selectable dBm reference impedances from 50 Ω to 1200 Ω

Accuracy (9% to 100% full scale, 18°C to 28°C, 90-day specification):
• AC: ±% of reading or ±dB
• AC + DC above 2 mV: ±(10 digits or 0.5 dB)
• AC + DC below 2 mV: ±(100 digits or 5 dB)

Temperature Coefficient
• Above 2 mV: ±(2 digits/°C or 0.1 dB/°C)
• Below 2 mV: ±(20 digits/°C or 1 dB/°C)

Environmental
• Operating: 0°C to 50°C
• Storage: -40°C to +75°C
• Humidity: 80% RH

– Key Features

• Autoranging with HOLD and STEP UP capabilities
• Analog meter for peak and null adjustments
• Relative dB measurements
• Counter output converts input signals to 100 mV peak square wave for frequency counter interfacing
• PTI data bus compatibility with Fluke addressable instruments
• Compact design: 40.3 cm × 20.3 cm × 10.8 cm; 2.47 kg
• Power supply: 100–240 V ac ±10%, 45–440 Hz, 10 W maximum

– Typical Applications

• High-frequency oscillator testing
• Attenuator flatness measurement
• Amplifier response analysis
• Microphone level measurement
• Vibration and noise level testing
• Residual noise measurement on power supplies

– Compatibility & Integration

The 8921A integrates with Fluke’s PTI byte-serial data bus for automated test systems. Counter output enables frequency measurement via external counters without additional signal conditioning.