Run: Clicking on the Run button starts Run mode. Run mode is the simulation mode in which currents flow and circuits work. Physics works. Run mode lasts until stopped. Clicking on Run always starts the clock (when visible).

Though most circuits appear to function independent of time, the circuits in Electric & Magnetic Devices are actually time dependent. Capacitors rapidly charge and discharge, currents and bulb brightnesses change in response, and energy changes bars steadily grow (or occasionally decrease). The clock, when visible, records the time scales of these changes.

In Run mode, you can operate switches, change the turn frequency and direction of the generator's crankshaft, change the source of illumination for the solar battery, and change the length of the nichrome (copper) wire.

In Run mode, you cannot access the Standard Menu. In addition, all non-graphics elements and tools are not accessible (except as noted above). The only usable buttons are Stop, Pause and the graphics tools. In addition, you cannot access objects to move them or change their properties. With regard to the Graphics Palette, you can draw or place graphics objects and take snapshots. However, you cannot select, move or resize them.

Exception: To open an object's Properties Boxes during Run mode, depress the Control key and click on the object.

This exception provides you with a limited capacity to change circuit characteristics in Run mode. For example, you could change the resistance of a bulb or the material or thickness of a nichrome wire.

You can also change the scales and scale modes of ammeters and voltmeters without needing to stop the circuit simulation.