A Beginner’s Guide to Circuit Diagrams. The purpose is the same: getting from point A to point B. Literally, a circuit is the path that allows electricity to flow. If you know what to look for, it’ll become second nature. While at first you’ll just be reading them, eventually you will start creating your own.
Electrical symbols are the most commonly used symbols in circuit diagramming. Amplifiers (denoted by triangle shapes) increase the output signal in your circuit. Capacitors (parallel lines) store energy in your system, while resistors (zigzag lines) reduce current flow. All electrical engineering students should become familiar with these three shapes, as they are universally used in circuit diagrams. In Lucidchart, simply hover over the shape to see its name.
You can also search for a shape (e.g. Light bulb) using our Iconfinder and Google image search results feature for more shape image options. Unlike a resistor symbol, a transistor symbol is used to indicate amplification or switches of power.
There are three major transistor types: bipolar junction transistors (BJT), junction gate field-effect transistors (JFET), and metal oxide semiconductor field-effect transistors (MOSFET). Each type has its unique advantages and drawbacks. BJTs have high transconductance, whereas MOSFETs excel at low voltages.
A useful mnemonic device for remembering which transistors are PNP (positive-negative-positive) and which are NPN (negative-positive-negative) is “not pointing in” for NPN and “pointing in proudly” for PNP.