Abstract: An automatic gain controlled preamplifier for use with a laser detector and having a wide bandwidth and a low-noise figure. The preamplifier includes a voltage controlled input attenuator stage feeding a low noise wideband amplifier stage which drives an output amplifier stage. Each stage has independent AGC drivers which permit sequential control of the three stages by AGC voltages of different ranges. The output stage is controlled for low level signals, the attenuator stage for medium level signals, and the low noise stage by large signals, thereby maintaining the low noise characteristic for weak signals. The preamplifier is implemented in form for production as a monolithic circuit.