Keithley 6221 AC + DC Current Source

The Keithley 6221 is an AC and DC Current Source designed to generate up to 100 kHz smooth sine waves with the help of its 10MHz output update rate. This model comes with an integrated arbitrary and standard waveform generator within a frequency range of 1 mHz to 100 kHz frequency. In addition, the Keithley 6221 can offer as short as 5µs programmable pulse widths and also supports down to 50µs pulse I-V measurements. This Current Source is fully programmable via its front panel controls. However, for external controlling it comes equipped with multiple communication interfaces, which includes: RS-232, GPIB, and Ethernet.

 As an arbitrary function generator, the Keithley 6221 can generate ramp, square, sine, and four user-defined arbitrary waveforms. This model is one of the very few low current AC sources available on the market. This cost-effective source offers sourcing of currents (AC) from 4pA to 210mA. The output voltage compliance of this source can be adjusted from 0.1V to 105V in steps of 10mV. Remember, the voltage compliance is critical where overvoltage could damage the circuitry or the device under test (DUT). 

The Keithley 6221 AC + DC Current Source is considered one of the most viable means for differential conductance measurements when it is used in conjunction with the 2182A Nanovoltmeter.  This model offers 10¹⁴Ω output impedance and provides stable current to variable loads. It has a 65000-point source memory as well, which allows the direct execution of current sweeps from the instrument.