What Are Block and Schematic Diagrams? | Reference Block diagrams are efficient at providing a concise overview of a complicated system, while schematic diagrams provide the detailed explanations of the parts that the system holds. Together, block and schematic diagrams are used to explain circuits. Schematic diagrams can also resemble a blueprint, such as a drawn representation of a full circuit. ICOM IC-751A SERVICE MANUAL Pdf Download. View and Download Icom IC-751A service manual online. IC-751A Transceiver pdf manual download. Block diagram - Wikipedia Usage. As an example, a block diagram of a radio is not expected to show each and every connection and dial and switch, but the schematic diagram is. The schematic diagram of a radio does not show the width of each connection in the printed circuit board, but the layout does. To make an analogy to the map making world, a block diagram is similar to a highway map of an entire nation.