Electronic symbols 































The diagram in high and to right represents a preamplifier for alternative signal . The alternative signal present on the basis is amplified , the out is taken on the collector .


The one which is under represents a regulated  power supply to continuous tension. The zener diode determines the value of  the tension that is present at out .



 On left is the diagram of a power supply that transforms a line tension


220 v ~ in a direct tension 12v regulated.


The regulator delivers a precise tension , more it is protected against


overloads and overheats .