schematic diagram
A simplified drawing that shows the structure or principle of something, often used in science, engineering, and instruction manuals.
This schematic diagram explains the operating principle of the circuit.
If you look at the schematic diagram in the textbook, you can clearly understand the structure of the cell.
Compound of 模式 (もしき, 'model' or 'pattern') and 図 (ず, 'diagram'). The term is a modern technical coinage.