Keysight 34420A – Nano-Volt/Micro-Ohm Meter, 7.5 Digit

• 7.5 digit resolution
• 30ppm accuracy
• 2500 readings/s
• DCV: 1 mV to 100 V
• 2 and 4-wire resistance ranges: 1Ω to 1 MΩ

The Keysight 34420A nanovolt / micro-ohm meter is a high-sensitivity multimeter optimized for performing low-level measurements. It combines low-noise voltage measurements with resistance and temperature functions, setting a new standard in low-level flexibility and performance.

An integral two-channel programmable scanner simplifies voltage comparisons. Built-in ratio and difference functions enable automated two-channel measurements without the need for an external nanoVolt scanner. Both channels share the same low-noise specifications to ensure accurate comparisons.

The 34420A combines its low-noise nano-Volt input circuits with a high-stability current source to provide precise low-level resistance measurements – no more hassling with the cost and complexity of an external current source. Three resistance modes are included:

• Standard
• Low power
• Voltage-limited for dry-circuit testing

Offset compensation is also provided to minimize thermal EMFs and associated errors.

Built-in ITS-90 conversion routines accept the calibration coefficients from your SPRT probe for direct temperature measurement and conversion. Thermocouples, thermistors, and RTDs are also supported.

The 34420A gives you the versatility to tackle your most challenging tasks, both on the benchtop and in your automated system. Standard features include RS-232 and GPIB interfaces, SCPI and Keithley 181 programming language, 1024-reading memory, scaling and statistics, and a chart recorder analog output.

The 34420A gives you the quality and reliability you expect from Keysight Technologies. From the Keysight proven > 150,000 hour Mean Time Between Failure to its standard 1-year warranty, Keysight stands behind you to bring a new level of confidence to your low-level measurements.

Certain resistance measurements require a very precise, low-level current source to prevent the device from self-heating or damage during testing. In general, accuracy improves with the magnitude of the voltage or current being measured. Therefore, it is important to keep the measurement voltage as large as possible for devices with low resistance values. The Keysight B2960B series 6.5 digit low noise power source satisfies these measurement requirements when combined with the 34420A.

The B2960B series is an advanced bipolar power supply/source. It can source either voltage or current with 6.5 digits of resolution while monitoring both voltage and current, allowing it to make a resistance measurement by itself. Since it supports 4-quadrant operations, the output polarities can be positive or negative. It can, therefore, source currents from 10 fA to 3 A (DC) or 10.5 A (pulsed) and voltages from 100 nV to 210 V.

The combination of the B2961B and 34420A provides superior performance for low resistance measurements. In the resistance measurement scheme shown to the right, the 34420A performs the voltage measurement while the B2961B sources a precise current. In this configuration, the B2961B acts as the master and makes measurements at programmed intervals while simultaneously sending trigger signals to the 34420A to perform voltage measurements.

The 34420A can also measure resistance without the need for other instruments. The minimum resistance range is 1 Ω, and the maximum output current is 10 mA. However, the B2960B series can flexibly source currents of up to 3 A, thereby realizing measurements with a resolution 300 times higher and with sufficient accuracy when compared with the standalone 34420A. However, it is essential to define the appropriate test current, as discussed in the “Power dissipation effects” section of this document, because it also increases the power dissipation and self-heating effects.