Interactive Load Line Superimposition
As the cursor is moved across the tube's plate curves, the readouts at the top of the form display the XY values of the cursor's position. When the left mouse button is clicked, the load line is displayed with the bold blue line, and the plate voltage and current marked by the right angle red line. Furthermore, the needed B+ voltage and idle current, along with the plate and plate resistor dissipation, are displayed in the middle readouts.

Printing a Copy of the Curves
Pressing the "Print" button will print a large copy of the plate curves, the tube's base pin out schematic, its profile, and the essential tube characteristics. Print a set of curves and break out a ruler and look for the sweet spots. Or burn off a copy of each tube and make your own tube manual.