In the following video a colleague of mine compares two methods for measuring varying or dynamic currents: using a current probe versus using seamless ranging. Seamless ranging is an Agilent only technology found in the N6781A and N6782A SMU modules. Seamless ranging technology allows the power source to measure the current flowing through it and transition from one current measurement range to another as the current varies. All with no glitches or discontinuities in the output power. It provides the user with a tremendous amount of dynamic current measurement range which can be useful when doing power and battery optimization measurements on devices that go through various standby (low current) and transmit (high current) cycles. The figure below shows a graphical representation of using seamless ranging to measure dynamic current.
From the video we can see that although current probes are great tools for measuring high current they are a poor solution for measuring low level current and small current transitions. Seamless ranging on the other hand provides a very high resolution look at a varying current profile over a wide dynamic range.
To see more of seamless ranging in action check out the YouTube video Agilent Battery Drain Demo: Seamless Measurement Ranging on the N6781A. If you have anything to add to this post please use the comments section below and if you have any questions feel free to email me.