Keithley 6221/2182A/E Digital Multimeter DMM - Keithley 6221, The Keithley 6221 is a Digital Multimeter (AC and DC Current Source) that combines ease of use with exceptionally low current noise. It is ideal for applications in test environments ranging from R&D to production, especially in the semiconductor, nanotechnology, and superconductor industries. The 6221 is the only low current AC source on the market. Before its introduction, researchers and engineers were forced to build their own AC current sources. The multimeter is fully programmable via the front panel controls or from an external controller via RS-232 or GPIB interfaces; the 6221 also features an Ethernet interface for remote control from anywhere there's an Ethernet connection. The multimeter can source DC currents from 100fA to 105mA, and source AC currents from 4pA to 210mA peak to peak. The output voltage compliance of either source can be set from 0.1V to 105V in 10mV steps. The 6221 offers tools for defining curre