The transfer function—gain and phase as a function of frequency ... If you don’t have one available, you can make the measurements with an oscilloscope, a signal generator, and a standard transformer.

The block diagram shows how three low-power audio amplifiers (LM386) are configured to implement a triple-waveform generator at one ... maximum output power is a function of the LM386 chosen ...

But designers without access to one can create a simple circuit that uses a function generator and oscilloscope to generate JFET transfer and characteristic curves. The circuit can also be ...