What are the main differences between J2100A injection transformer, J2110A solid state injector and the J2111A current injector?

The J2110A is a solid state voltage injector, offering lower noise and wider bandwidth (DC-50+mhz) than a transformer.  The J2110A has a 25 ohm output impedance and is limited to +/- 10v input and output levels.  Picotest offers two transformers, the J2100A and the J2101A.  The difference between the two transformers is the bandwidth.  The J2100A offers a low end bandwidth of 1Hz satisfying low frequency measurements such as PFCs, while the J2101A is designed for a higher frequency range starting at 10Hz.  The J2101A is most beneficial for linear regulators, LDOs and switching regulators.  The J2111A is a current injector with a transconductance of 10ms.  The J2111A is a current sink (two actually, one for positive voltages and one for negative voltages.  Both are contained inside the J2111A; steering electronics automatically choose the correct path.  The device has a precision current port allowing a current to be injected to create a small signal step load and also for output impedance, PSRR and reverse transfer measurements.  The device can sink current from voltages above 0.7V and below -0.7V.  It will not operate between -0.7V and +0.7V and cannot source current, only sink it.  The J2111A is our most popular injector and is the basis for the non-invasive phase margin measurement, which is derived from output impedance.