Circuit Idea/Putting yourself in the place of the device under study

Another heuristic technique is to mentally put yourself in the place of the electronic devices being studied. Thus we dentify with them (this is actually the concept of empathy known from Synectics). For this purpose, we replace active elements (transistors and operational amplifiers) with manually controlled elements and begin to perform their functions mentally. Through this empathy, we identify with them and can "feel" the circuit operation. For example, in the inverting voltage summer, we can replace the operational amplifier by a manually controlled voltage source, a null indicator, and an "actor".