HP / Agilent 4278A 1 kHz/1 MHz Capacitance Meter

The HP/Agilent 4278A is a precision capacitance meter operating at 1 kHz and 1 MHz, engineered for high-speed component inspection and quality control in production and laboratory environments. It measures capacitance, dissipation factor, quality factor, equivalent series resistance, and conductance with measurement speeds up to 153 measurements per second. The instrument incorporates an intelligent 10-bin comparator for automated sorting, zero adjustment for stray impedance compensation, and auto-calibration capability with external standards.

– Technical Specifications

Measurement Frequencies: 1 kHz and 1 MHz

Measurement Parameters: Capacitance (C), Dissipation Factor (D), Quality Factor (Q), Equivalent Series Resistance (ESR), Conductance (G)

Capacitance Accuracy:
• 1 kHz: ±0.07% of reading + 0.025% (full scale)
• 1 MHz: ±0.05% of reading + 0.02% (full scale)

Dissipation Factor Accuracy:
• 1 kHz: ±0.0005 with 0.00001 resolution
• 1 MHz: ±0.0002 with 0.00001 resolution

Measurement Ranges:
• 1 kHz Normal Mode: 7 decade ranges, 100 pF to 100 µF full scale; 100% overranging available (max. 200,000 counts) when D ≤ 0.5%
• 1 MHz Normal Mode: 11 binary ranges, 1 pF to 1024 pF full scale; 25% overranging when D ≤ 1%
• 1 MHz High Accuracy Mode: ±30% of user-defined nominal value, maximum 2048 pF, when D ≤ 0.05%

Test Signal Level: 0.1 Vrms to 1 Vrms in 0.1 Vrms steps; ±10% accuracy (C ≤ 20 µF)

Measurement Speed Modes:
• SHORT: 6.5 ms (153 measurements/sec)
• MEDIUM: 10 ms (100 measurements/sec)
• LONG: 21 ms (47 measurements/sec)

Display: Dot-matrix LCD with 4, 5, or 6 digit resolution

Temperature Stability (LONG integration, 12±5°C):
• C: ≤0.01%/°C
• D: ≤0.0001/°C (1 kHz and 1 MHz Normal Mode); ≤0.00004/°C (1 MHz High Accuracy Mode)

Reference Data Stability (LONG integration, constant temperature):
• C: ≤0.01%/day
• D: ≤0.0001/day

– Key Features

• Parallel and series measurement circuit modes
• Intelligent 10-bin comparator (9 bins for capacitance, 1 no-go bin)
• Pushbutton zero adjustment for handler and fixture impedance compensation
• Cable length compensation selectable for 0, 1, or 2 meters
• Internal, external, or manual trigger modes
• Power: 100/120/220 Vac ±10%, 240 Vac +5–10%, 48–66 Hz

– Typical Applications

• Production line capacitor inspection and sorting
• Component quality assurance and acceptance testing
• R&D characterization of capacitive devices
• High-speed automated testing with comparator-based binning

– Compatibility & Integration

The 4278A accepts external calibration standards and integrates zero and cable compensation functions for use with automated test handlers and fixture systems.