How to Read a Schematic Diagram?

What is a Schematic Diagram? A schematic diagram is a drawing that represents an electronic circuit. It is important to know how to read and draw a schematic if you want to learn electronics. A schematic is the language of electronic engineers and it is used to share ideas and designs. To be able to understand these ideas you must know how to read and create schematic diagrams.

Electronic components are represented by schematic symbols, we have already covered the most common ones in the Electronic Components Symbols page. We also need to represent the wires connecting the components together, see the table for a list of representations:

Normal connections are just drawn as a single line between components. When two wires cross and they are connected, the connection is indicated with a dot where they cross. When two wires cross but they are not connected, the two wires just cross each other without the dot or the one wire is drawn as going over the other wire.  

Let’s have a look at the PICAXE-08 programming interface schematic to see how the rules are implemented in the schematic. Pin 2 of the PICAXE is connected to a 22k resistor. The other side of the 22k resistor is connected to a 10k resistor as well as pin 2 of the 3 pin male polarised header connector.  Pin 7 of the PICAXE is connected to pin 1 of the header connector but is not connected to pin 8 or pin 1 of the PICAXE. The two voltage rails are also shown with 5V for +5V and 0V for the ground connection.