I've seen schematic diagrams with transistors that have a little circle right where the base connects with the rest of the transistor. From the context it seems like the behavior is that the resistance between the emitter and collector goes way down if the base voltage is LOW, not high. Does such a transistor exist? If it does, how can I create a schematic diagram with it, using the tools on this forum? I couldn't find a transistor with such a circle among the items I can choose from.
You can draw the schematic diagram by inserting the symbol at gate/block level but not the transistor level (e.g. P-mos, N-mos, etc).
To insert the symbol, Create a new schematic file (.bdf), click on Symbol Tool -> choose the gate/block from the Libraries.