THE value of block diagrams in geographical and geological instruction cannot be questioned, but many teachers find these difficult to draw, especially on the blackboard, at short notice.

Block diagrams close block diagramA diagram of a ... use simplified universal symbols to represent the electronic circuit and its components. A circuit diagram shows how the components are connected.

These diagrams and symbols are the keys to quickly and efficiently understanding even the most complex ... There are several different types of engineering hardware drawings, including: Block diagrams ...