N7909A - 

The N7909A power dissipater unit adds current sinking or two-quadrant operation to any Advanced Power System (APS) N6900A or N7900A power supply. Each N7909A provides up to 1 kW of current sinking capability to an APS power supply, so you will need two N7909As to achieve full two-quadrant operation of a 2-kW APS supply. You can use a single N7909A unit with a 2-kW APS power supply to achieve 50% current sinking capability. The N7909A form factor is 1U and full rack width. N7909A connects to an APS power supply via a two-wire power connection and a communication connection to provide continuous two-quadrant operation. The connections are located on the rear panel of both the N7909A and the supply.

Note that the N7909A does not operate as a standalone instrument. It only works with an APS power supply. Additional information on the APS's 2-quadrant operation:

The APS provides programmable +/- current waveform capability to fully utilize the two-quadrant operation

The APS provides +/- current limit settings to ensure your device is operated in its allowable range

By default, the APS's current sink capability will perform down programming for pulling down voltage levels when it is connected to loads with stored energy, for instance loads with a large amount of parallel capacitance at their input.

All these capabilities are also available when you use a standalone APS power supply's 10% rated output current sinking capability without the N7909A power dissipater unit