The Keysight/Agilent/HP 427A Option 01 Voltmeter is a portable, self-contained instrument for precision AC and DC voltage measurement, along with resistance testing. Built with solid-state components and housed in a compact form factor, it delivers reliable performance across laboratory and field environments. Option 01 adds AC line power capability (115 VAC or 230 VAC selectable), complementing the internal 22.5 V battery for operational flexibility.
Technical Specifications
AC Voltage Measurement
• Ranges: 10 mV to 300 V RMS full scale (1, 3, 10 sequence; 10 ranges)
• Frequency response: 10 Hz to 1 MHz
• Input impedance: 10 MΩ || 40 pF (10 mV to 1 V ranges); 10 MΩ || 20 pF (3 V to 300 V ranges)
• AC rejection: Superimposed peak AC voltages 100× full scale (60 Hz and above) produce <1% reading error
• Overload protection: 300 V RMS (1 V range and below); 425 V RMS maximum (above 1 V range)
• Response: Average-value responding, RMS-calibrated for sine wave input
DC Voltage Measurement
• Ranges: ±100 mV to ±1000 V full scale (1, 3, 10 sequence; 9 ranges)
• Accuracy: ±2% of full scale (0°C to 50°C)
• Input resistance: 10 MΩ on all ranges
• Overload protection: 1200 VDC on any range
Resistance Measurement
• Ranges: 10 Ω center scale to 10 MΩ center scale (7 ranges)
• Accuracy: ±5% of reading at mid-scale (0°C to 50°C)
• Common terminal polarity: Negative
Power & Physical
• AC line operation: Selectable 115 VAC or 230 VAC (±20%), 50 to 1000 Hz
• Battery: Internal 22.5 V dry cell (e.g., Eveready No. 763 or RCA VS102)
• Power dissipation: <0.5 W maximum
• Dimensions: 130 mm W × 155 mm H × 200 mm D
• Weight: 2.5 kg
• Display: Mirrored analog meter
• Includes three-conductor grounded power cable
– Key Features
• High input impedance (10 MΩ) minimizes circuit loading on all voltage ranges
• Wide AC frequency capability extends from 10 Hz to 1 MHz
• Dual power: AC mains or internal battery for field portability
• Robust overload protection across measurement modes
• Compact 1/3 rack-width design with carrying handle
– Typical Applications
• Field troubleshooting and maintenance in AC/DC circuits
• Bench verification of power supply outputs and signal levels
• Resistance continuity and component value measurement
• AC signal monitoring in audio and RF test environments
– Compatibility & Integration
Originally manufactured as Hewlett-Packard (HP), later branded Agilent Technologies, and currently Keysight Technologies. Accepts standard test leads on VOLTS and COM (common) input terminals.
