tams elektronik PZS-3 Manual page 16

English
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).
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.
Rectifiers
Rectifiers convert alternating into direct voltage. They have
four pins: two for the input voltage (a.c. voltage) and two
for the output voltage (d.c. voltage). The pins for the
output voltage are polarized.
Transistors
Transistors are current amplifiers which convert low signals into
stronger ones. There are several types in different package forms
available. The type designation is printed on the component.
Transistors for a low power rating (e.g. BC types) have a
package in form of a half zylinder (SOT-package).
Transistors for a high power rating (e.g. BD types) have a
flat package (TO-package), which is in use in different
versions and sizes.
The three pins of bipolar transistors (e.g. BC and BD types)
are called basis, emitter and collector (abbreviated with the
letters B, E, C in the circuit diagram). T
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PZS-3