HP (Hewlett-Packard) 205AG is an audio signal generator that provides accurate gain or frequency response measurements. It is typically used for amplifier gain measurements, network frequency response, source of voltage for distortion measurements, broadcast transmitter audio response, loudspeaker response, general laboratory application, and production testing. Its key features and capabilities include:

• Frequency range: 20 cps to 20 ke in three decade bands (x1, x10, x100).
• Calibration accuracy: Within +2% at normal ambient temperatures.
• Output: 9 watts maximum into resistive loads of 50, 200, 600 and 5000 ohms.