Hello,
I think you mean the "E" device in a pspice program.
It is a linear device where
"output voltage" = C*(input voltage).
"Input voltage" is voltage between two nodes that can be everywhere in your circuit.
C = gain, can have negative value also.
I use it frequently in mixed electronic and system level design work.
You may also want to use the "arbitrary voltage source".
Here you can specify a (non-linear) mathematical equation based on current through components and voltages between nodes (or across components).