The Model 2505 is a multi-function instrument which is ideal for users that must make a large variety of sophisticated measurements. A single package, contains a Gain Phase Analyzer (Frequency Response Analyzer),  Phase Angle Voltmeter with a null detector, Function Generator,  Pulse Generator,  Spectrum Analyzer,  Digital Sampling Oscilloscope,   Wattmeter,  Phase Meter and  Complex Impedance Bridge. These internal instruments cover the frequency range from dc (10mHz for the ac instruments) to more than 2MHz.

Each of these internal instruments may be used independently or in an internally correlated fashion. By selecting the internal Function Generator and the two Voltmeters, the user can obtain dual gain-phase data for two outputs of any network he is testing. This is particularly useful for making Bode plots to check the stability of networks having feedback. These plots can be displayed in several formats using the oscilloscope capability of the Model 2505. Because of the floating inputs, the measurements can be made across network components with neither side connected to ground.

The Spectrum Analyzer feature can be used to observe the harmonic content of complex, periodic input signals. This proves to be especially useful for examining current waveforms to ensure that they do not exceed the requirements placed on harmonics.

As a true rms Wattmeter, the Model 2505 is ideally suited to measure core loss, input power to ultrasonic transducers, power consumed by switching power supplies, and many other devices operating at higher frequencies. It also performs exceptionally well with measurements at 50Hz or 60Hz.

The Complex Impedance Bridge function permits the user to measure Resistance, Inductance and Capacitance at frequencies from dc (Resistance only) to 2MHz. Secondary functions such as Q (quality factor), D (dissipation factor), and ESR (equivalent series resistance) can also be measured over the same frequency range.