Circuit Idea/Carrying Out "Man-Controlled" Experiments

To "feel" the operation of more abstract electronic devices, they can be manually emulated and then their evolution to fully automatic can be "played out". Thus, for example, the role of an operational amplifier in negative feedback circuits can be performed:
 * first by a "manually controlled voltage source",
 * then by a personal computer with analog I/O peripherals and appropriate software,
 * finally by a real operational amplifier.

In this way, by actually "playing" the evolution of an electronic circuit from "manual" to fully automatic, the person mentally identifies with the studied object (personal analogy, empathy), imagines how it performs its functions, and thus understands even better its action.