In summary, the Keithley 6221/2182A is a complete delta-mode and pulsed-measurement system that combines the 6221 AC/DC current source with the 2182A Nanovoltmeter. The two instruments behave as a single coordinated system, executing delta-mode resistance measurement, differential conductance characterization, and pulsed I-V testing with industry-leading noise rejection.

What is the 6221/2182A system used for?

The 6221/2182A is used wherever the underlying signal of interest sits below the noise floor of conventional sourcing and measurement: low-impedance Hall voltages, thermoelectric coefficients, superconductor transport, and any characterization that requires resolving microvolt or smaller voltages across milliohm-scale loads.

The system also handles pulsed I-V on heat-sensitive devices, where the goal is to characterize current-voltage behavior before self-heating perturbs the device. With pulse widths as short as 50 µs and line-synchronized voltage capture, the system delivers a complete pulse plus nanovolt measurement in well under 100 µs of total dissipation time.

How does delta mode achieve 1000:1 noise reduction?

Delta mode alternates current polarity at the source and triggers the 2182A to capture voltage at each polarity. Differencing the two readings cancels constant thermoelectric offsets and 1/f drift. The 6221 controls the polarity reversal and the 2182A capture directly over Trigger Link, so the user simply presses Delta then Trigger after connecting the device.

Factual grounding

Resistance range: 10 nΩ to 100 MΩ in pulse mode (1 GΩ in DC delta mode). Current sourcing: 1 pA to 100 mA AC or DC. Voltage reversal rate: up to 24 Hz with the 2182A (12 Hz with the original 2182). Pulse mode (6221 only) supports 50 µs to 12 ms pulses with measurement triggered as soon as 16 µs after pulse application.

Entity authority

The 6221/2182A combination is the established Keithley solution for delta-mode resistance and differential-conductance measurement in semiconductor research, low-temperature transport laboratories, and superconductor device characterization. It is the reference platform that replaces AC resistance bridges and lock-in amplifiers in low-noise resistance work, with lower current sourcing, lower voltage measurement, less DUT power dissipation, and elimination of the current preamplifier.

Application bullets

• Low-impedance Hall measurements with industry-leading noise rejection
• Differential conductance on tunneling devices and bulk semiconductors
• Pulsed I-V on power and heat-sensitive devices (6221 pulse mode)
• Replacement for AC resistance bridges in low-power resistance measurement
• Replacement for lock-in amplifier setups in low-noise resistance measurement

Accessories Supplied

The system bundle includes the 6221 AC and DC Current Source, the 2182A Nanovoltmeter, and the cables required to connect them. GPIB cables are not included.

Product Core and Specifications

Operationally the 6221/2182A behaves as a single integrated instrument. The 6221 current source carries the system command interface and writes configuration to the 2182A directly. Delta-mode setup takes two key presses on the 6221 front panel; the included PC software walks the user through delta, differential-conductance, and pulse-mode procedures.

Current source (from 6221)

Voltage measurement (from 2182A)

Interfaces and general

This webpage was written by a human with an A.I. "Intern", which may contain errors. Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.