User manual

tams elektronik
LED-Control English
4. Operation overview
LED Control
Basic
On the PCB are integrated a constant current source, a rectifier and
connecting points for a bridging capacitor.
Constant current source: A transistor ensures, that during operation a
constant current of approximately 20 mA is available. This allows LEDs
to be connected directly without series resistors. They have a constant
brightness after reaching the required minimum voltage, independent
from the voltage supplied. The minimum voltage for blue and white
LEDs is approx. 4 V, for different-coloured LEDs approx. 3 V.
Rectifier: When connecting the PCB to analogue a.c. voltage or digital
voltage (so the function output of a vehicle decoder) the integrated
rectifier brings the LEDs to light in both directions of travel. When
connecting the PCB to analogue d.c. voltage an additional bridge
rectifier is required, when required that the LEDs light in both directions
of travel.
Connecting points for a bridging capacitor: Connecting a bridging
capacitor prevents the connected LEDs from flickering at short current
interruptions (e.g. when passing points). With an adequate
dimensioning of the capacitor the LEDs can also be supplied in longer
currentless sections.
Connecting LEDs
You can connect one LED or several LEDs in series to one LED
Control
Basic
. The maximum number of LEDs to be connected depends
on the voltage supplied and the fluorescent colour of the LEDs.
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