This applet plots up to 10 Planck radiation law curves for arbitrary temperatures in the range 3000-30,000 K, with the temperature for each case selected by the user with the slidebar at the bottom: slide the bar to the temperature desired and click "New" for each case to be plotted. There are three scales of slidebar movement: large moves by dragging the selector, medium (10 or 100 degrees) by clicking in the space between the selector and the right or left end, and 1 degree at a time by clicking the right and left arrows on the slidebar.
You may choose linear, log, and log-log plot modes using the choice menu at the upper right. For the linear plots you may choose whether to normalize all curves to unit height, or let the curves have their correct relative heights by toggling the Norm checkboxes. You may also choose whether to indicate the UV, visible, and IR ranges of wavelengths explicitly by toggling the UV-V-IR checkboxes. The "Clear" button clears all plots.