Opisometer Geology supplying a duplicate-value option for

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

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

and field magnet for direct observation as students trace how current produces rotation in a closed magnetic circuit

driving performance with motor-generator #2

Used to draw electrons from glass and ebonite rods during rubbing

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.