All of them will be shown step by step. Typical circuits textbooks tell us that there are four basic feedback topologies. One of the tasks of feedback analysis, it would seem then, is to identify to which of the four basic topologies a given feedback circuit conforms. But this is misleading. This article attempts to clarify the inevitable confusion.
Actual circuits can also have additional associated transmittances.
The more general feedback topology is shown in Figure 2. T i and T o are outside the feedback loop but are included because they commonly occur with feedback circuits. Sometimes it is not obvious from a circuit diagram that such blocks should be included. The arrows represent causal constraints, pointing from output to input. The input multiplied by the transmittance written in the block is the output.