HP / Agilent 42841A Bias Current Source

The HP/Agilent 42841A Bias Current Source is a DC bias accessory for Agilent/Keysight impedance analyzers, delivering stable current to devices under test for impedance characterization across varying bias conditions. It enables precise measurement of components - particularly inductors - under simulated operational currents, essential for R&D, quality control, and production testing in switching power supplies and RF applications.

Technical Specifications

• 0.00 A to 1.00 A: Resolution 0.01 A, Accuracy ±(1% + 5 mA)


• 1.1 A to 5.0 A: Resolution 0.1 A, Accuracy ±2%


• 5.1 A to 20.0 A: Resolution 0.1 A, Accuracy ±3% Maximum Output Current:


• 10 A with 4285A


• 20 A with 4284A (single unit)


• 40 A with 4284A (two units in parallel)


• 40 A with E4980A (two units in parallel) Frequency Range (dependent on host analyzer):


• 20 Hz to 2 MHz with E4980A


• 20 Hz to 1 MHz with 4284A


• 75 kHz to 30 MHz with 4285A

Key Features

• Front panel control via compatible LCR meter


• Modular design supporting single or dual-unit configurations for higher current requirements


• Tiered accuracy specifications: ±(1% + 5 mA) at sub-ampere levels, ±2–3% at higher ranges


• Installation Category II, Pollution Degree 2 per IEC 1010-1


• Indoor-use only, standard AC power input

Compatibility & Integration The 42841A integrates with:

• E4980A (Option E4980A-002)


• 4284A (Option 4284A-002)


• 4285A (Option 4285A-002) Complete measurement systems require compatible bias test fixtures (42842A, 42842B, or 42842C), appropriate test leads, and bias current cables per configuration. Dual-unit 40 A configurations demand the 42842B fixture and 42843A bias current cable.