The HP/Agilent 432A is an automatic self-balancing power meter for RF and microwave measurement using temperature-compensated thermistor sensors. It delivers true average power readings with high accuracy across a wide temperature range while minimizing thermoelectric errors. The instrument combines an analog taut-band meter display with a 13-position calibration factor control that directly compensates for sensor losses, eliminating manual calculations and simplifying field operation.
Technical Specifications
• Measurement Principle: Self-balancing bridge circuit measuring thermistor sensor output voltage
• Accuracy: ±0.2% ±0.5 µW over wide temperature range; thermoelectric error reduced to negligible levels
• Power Range: 10 µW, 30 µW, 100 µW, 300 µW, 1 mW, 3 mW, and 10 mW full scale
• dBm Display: -20 dBm to +10 dBm full scale in 5 dB steps
• Noise: <0.25% of full scale peak (typical)
• Response Time: 35 ms time constant at recorder output
• Zero Carryover: 100 mm
• Calibration Factor Control: 13-position switch (100% to 88% in 1% steps)
• Power Consumption: 1.5 watts
• Input Power: 115 to 230 Vac ±10%, 50 to 400 Hz
• Dimensions: 130 mm W × 155 mm H × 279 mm D
• Weight: 2.3 kg net
– Key Features
• Automatic fine zero operation via front-panel switch
• Recorder output proportional to indicated power (1 V at full scale, 1 kΩ impedance)
• Vcomp and Vrf rear-panel outputs for differential measurement with external DVM
• Optional BCD output in 8-4-2-1 code, TTL compatible (432B model)
– Compatibility & Integration
The 432A operates with HP 478A and 8478B coaxial thermistor mounts, and 486 series waveguide thermistor mounts. These sensors provide frequency coverage from 10 MHz to 40 GHz with NIST-traceable calibration factors and effective efficiency data.
