The LDP-3840B precision pulsed laser diode current source introduced by ILX Lightwave is a microprocessor-based instrument for pulse testing and characterizing low- and medium-power laser diodes. It provides up to 3 A of low-noise peak pulse current, with adjustable pulse widths from 100 ns to 10 ms. Features include a GPIB/IEEE-488 interface, and input and output triggers to control pulses and initiate corresponding measurements without a command program. Safety features include current limits, output shorting circuits, AC line filters and double-shielded transformers to suppress laser-damaging transients. Rise and fall times are <50 ns, and overshoot is <5%. Duty cycle and frequency are adjustable, and pulse polarity is user-selectable.