Opisometer Geology supplying a duplicate-value option for

supplying a duplicate-value option for paired-bench experiments on capacitor energy storage

Single large transparent plate filled with iron-rod plotting compasses

driving performance with motor-generator #2

sized to read one step up from the 0-1A meter when student circuits draw past the lower meter's full-scale deflection

this concave glass mirror at 100mm focal length runs at f/1 for vivid real-image demos and converging-reflection work

Opisometer Geology supplying a duplicate-value option forOpisometer with a knurled wheel on a threaded spindle, rolling along curved lines on maps, charts, and drawings to convert winding distance into straight line length for geography coursework.