A hierarchy of diagrams
The functioning of CSIRAC was represented by a hierarchy of diagrams with block diagrams at the highest level, logical diagrams at the next and schematic diagrams at the lowest .
A block diagram is a diagram of a system such as CSIRAC, in which the principal parts or functions are represented by blocks connected by lines, that show the relationships between the blocks. It is used to gain an overall understanding of the system.
A logical diagram is a more detailed graphical representation of one of the principal parts of CSIRAC. Each functional component is represented by a symbol. The diagram shows the connections between these components. In CSIRAC, each functional component consisted of several physical components such as vacuum tubes, resistors and capacitors. Logical diagrams are used to understand the functioning of the circuit.
A schematic diagram shows the detailed connections between all the components in a circuit. They are used to build the circuit and later for testing. For CSIRAC, the most common components were vacuum tubes (valves), capacitors and resistors. Schematic diagrams are also known as circuit diagrams.
Other types of diagram
A timing diagram is a graph showing how a set of signals changes with time. The diagram shows the time relationship between different signals in a functional part of CSIRAC. They were used in designing the different parts and later for testing.
Mechanical drawings show the physical construction of a component. They were used to fully and clearly define requirements for the manufacture of CSIRAC's hardware.