Transistor Devices' XBL series of electronic loads offers 800, 2000, 4000, and 6000 watt models with built-in Ethernet, GPIB, and RS232 programming capabilities. With its digital control technology, the series provides increased reliability and performance, making it suited for testing power supplies, batteries, fuel cells, and dc power sources. All models offer master/slave parallel capabilities and closed box calibration. High-power models incorporate variable speed forced-air cooling to assure a quiet environment. Features include 16-bit digital control; remote control and monitoring via Ethernet (TCP), Telnet, and Web browser; and fault tolerant MOSFET modules.