The first thine which you should know in building electrical circuits for an electrical device are basic theories in electronics. Know the different components used and how to connect them properly to each other. Then study how to read and make schematic diagrams which are graphical representations of an electrical circuit using symbols and images.

Doing so is essential when there is a particular device you want to make but is still confused with some parts of the process. This might be something a little advance such as voltage divider which produces an output that is a portion of its input. But learn or review first the theories in basic electronics to understand better the more advanced stuffs.

Start with identifying the two types of electricity which are alternating current or AC and direct current or DC. The direction that electrical signals flows in AC is reversing constantly or alternating and the reversal rate is measured in Hertz. The flow in DC though is one direction from power source to ground and commonly found with batteries.

A closed circuit is when the electric current is allowed to pass through a path from power source to ground which normally indicates a device is functioning. While an open one breaks this path and will prevent the movement just like in turning off a machine. This is done with a switch so you could alternate between them instead of removing the source.

Components create resistance when current pass through them from positive voltage to ground and if these two are directly connected, it would cause a short circuit. This direct connection will result in explosion, fire, breaking or overheating which must be avoided. A switch would not add resistance so simply putting one without other parts is not advisable still.

Wiring things together can be done in two ways which are called series and parallel with the former indicating that all components are wired after the other. While the latter indicates that the parts are wired next to each other and which makes electricity pass them simultaneously. Both ways could be used in building your own circuits.

Adding resistance into circuits is done with resistors and they reduce current flow and are also available in a variety of values measured with ohms. They have wattage ratings also and their value is indicated by colored bands around their body. You could learn reading these bands or look up for graphs that helps in calculating their values.

Capacitors are components that stores electricity then discharges them when it drops and is measured in Farads with common ones being microfarad, nanofarad and picofarad. The commonly used types of capacitors are ceramic disc and electrolytic. The former being non polarized and the latter polarized requiring one of its leg to be properly connected with the power or ground.

Diodes are polarized components allowing current to pass through one direction and would cause a voltage drop. One of its side is called cathode which connects to power and the other is anode. These are just samples of the basic theories you must learn in making electrical devices.