Electronics is great and it is all about the control of currents and voltages in a circuit. By using the right components with the right value in the right order, the most fantastic applications can be created. Let’s start looking closer to the symbols that are used when we talk about components in a circuit.

Common symbols/components

European symbols

Starting with the generic symbol of a battery, or a DC-power supply. The “+” indicating the positive connection and the “-” the minus or zero. Often the zero is also referring to ‘ground’. This is the fundament of a circuit: the power supply.

A line is referring to a wire which is a electrical connection between multiple points in a circuit. When two lines cross, a dot indicates a junction – there is a connection. When two lines in a circuit diagram cross without a junction – there is NO connection.

There are a lot of different symbols indicating ‘Zero’ or ‘Ground. The symbol with the 3 lines is indicating earth literally. A connection to the physical ground. Ground (zero) is a reference.

Capacitors are simple passive devices that can store an electrical charge on their plates when connected to a voltage source.
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A resistor is a component indicating ‘resistance. The bigger the resistance, the smaller the current through the resistor. Resistors can have many differents packages. In general 1/8 watt resistors are used in audio circuits referred to in this website. The value of the resistor is indicated with colored rings. Check this link for the values.

Switches can be found in lots of packages or configurations. A switch creates a connection (ON) or an infinite resistance (off).

The common symbol for an amplifier is a triangle. It is not referring to specific type, but a general indication that a signal is ‘amplfied’.

A coil is a a long wounded wire (around a core) creating resistance for higher frequencies. Therefor coils are mainly used in filters.

An Operational Amplifier, abbreviated opamp. This ideal electronic building block has an inverting and a non inverting input and one output. Check this page for more details.

A potentiometer is a variable resistor.

A diode conducts current in one way only – therefore its symbol looks like an arrow. The “A” indicates the Anode (positive) and the “C” the Cathode (negative). The diode with the two arrows indicate a Light Emitting Diode or LED.

One of the most important components of ‘modern’ electronics is the transistor. The transistor exists in many different shapes. The most common ones are NPN and PNP. Check this short movie of the transistors for more details.

A Field Effect Transistor or FET. The bg difference between a transistor (BJT) and a FET is the way it is driven. a transistor is current driven and a FETis voltage driven.