Some active building blocks.
| Class | PWM | PWM square wave oscillator with duty cycle controlled by an input ranging from 0-1, where 1 is 100% duty cycle. |
| Class | FileSource | File source providing piecewise-linear source voltage values vs. time. |
| Class | Capacitance_Meter | Capacitance meter using a DC bias that ramps up and a sinusoidal signal source, with current sensing on return leg. |