Model 2281S-320-6 has three functions (high precision power supply, battery test and battery simulator) To configure as a power supply from the front panel for 3.8V at up to 4A: Select Power Supply from the main menu. Press ENTER Select Vset. Use the up/down and right/left arrow buttons to enter in 3.8V. OR use the data keypad to enter 3.8V. and press ENTER. Select I-Limit. Use the up/down and right/left arrow buttons to enter 4A, Or use the data keypad to enter4A. and press ENTER. Press OUTPUT, and 3.8V should appear at the output terminals and the display.