What is the difference between the Keithley 2636A and 2636B?
In addition to retaining all the features of the Model 2636A, the Model 2636B has 6½-digit resolution, USB 2.0 connectivity, and software command emulation of the Model 2400 SourceMeter SMU Instrument that enables easy migration of legacy test code. The minimum voltage and current have an added range in the B model. See below:
2636B Voltage Min/Max = 100nV/200V, Current Min/Max = 0.1fA/10A pulse
2636A Voltage Min/Max = 1uV/200V, Current Min/Max = 1fA/10A pulse