FCS-3
English
Seite 27
Special features of the additional components
Resistors
Resistors reduce current. Their mounting orientation is of no
importance. The value of resistors for smaller power ratings
(under 5 W) is indicated through colour rings. Every colour
stands for another figure. The added resistor has a value of
10 k
Ω
(colour rings brown - black – orange – gold).
Diodes
Diodes allow the current to pass through in one direction only
(forward direction). The diode type is printed on the body.
Diodes must be mounted in a given direction. The negative
end is marked with a ring.
Transistors
Transistors are current amplifiers which convert low signals
into stronger ones. They have three contacts. As they are
polarized, they have to be mounted in a certain direction. Die
BC-Types have a housing in form of a half cylinder (SOT-
housing). The three connecting points are called basis (B),
collector (C) and emitter (E).
Light emitting diodes (LEDs)
When operated in the forward direction the LEDs light. They
are available in several different versions (differing in colour,
size, form, luminosity, maximum current, voltage limits). The
longer lead of wired LEDs is always the anode (positive pole).
With SMD-LEDs the cathode normally is shown by a mark on
the housing.
Light emitting diodes should always be connected via a series
resistor which limits the current and prevents failure. With
circuits designed for the connection of LEDs the series
resistors are often integrated on the circuit board.
