HP / Agilent 41800A Active Probe, 5 Hz to 500 MHz

The HP/Agilent 41800A is an active probe engineered for high-impedance signal acquisition across the audio through VHF spectrum. Operating from 5 Hz to 500 MHz, it delivers minimal circuit loading and superior signal fidelity—essential for accurate characterization in sensitive RF and analog circuits. The 100 kΩ input impedance and 2–3 pF input capacitance preserve circuit behavior during measurement. Its 0 dB gain (±0.5 dB @ 50 MHz) maintains signal integrity, while low noise at 10 nV/√Hz (≥300 kHz) and low distortion enable reliable acquisitions across demanding applications.

– Technical Specifications

• Frequency Range: 5 Hz to 500 MHz
• Input Impedance: 100 kΩ
• Input Capacitance: 2–3 pF
• Gain: 0 dB (±0.5 dB @ 50 MHz)
• Noise Spectral Density: 10 nV/√Hz at ≥300 kHz; +3 dB/Oct at <300 kHz
• Maximum Input (AC + DC): ±40 V (probe alone)
• Maximum Input (AC only): 0.5 Vrms (probe alone); 0.5 Vrms (with 1:1 divider); 5 Vrms (with 10:1 divider); 30 Vrms (with 100:1 divider)
• Output Connector: BNC

– Key Features

• High input impedance minimizes circuit loading and preserves signal authenticity
• Active design reduces noise and distortion for cleaner measurements
• Retractable metal sleeve protects probe tip against physical damage and ESD
• Compact, lightweight form factor enables access to confined test points
• Switchable attenuation dividers (1:1, 10:1, 100:1) extend voltage range to 30 Vrms
• 0 dB unity gain maintains reference signal levels

– Typical Applications

• Spurious level, harmonic, and noise measurements with spectrum analyzers
• Gain, phase, and group-delay characterization at the circuit level with network analyzers
• Circuit signal analysis for audio, video, HF, and VHF band designs
• Evaluation of sensitive RF circuits and signal paths

– Compatibility & Integration

Direct compatibility with Agilent network and spectrum analyzers providing probe power—such as the HP 4195A. External probe power via Agilent 11899A, E3620A, E3630A, or E3631A supply using the 87405-20012 cable supports operation with instruments lacking integrated probe power delivery.