gepulste Rücklichter | Posts 16+

olli wrote:

Hi, Sure, you can filter, but each filter costs a few extra cents.

...and not just in a single STG (System Terminal Gateway), but in all those installed within the data bus network. Therefore, it is a more practical (and cheaper) solution to avoid interference altogether.

Quote:

And when you consider that millions of people voluntarily spend their time in front of flickering screens, or have done so in the past, or sit under flickering fluorescent lights...

Good comparison!

Arno wrote:

... However, what I meant was that instead of, for example, 50 Hz, the LEDs could be clocked at 100 Hz (or 200 Hz instead of 100 Hz) to minimize flickering.

So that the occupants will eventually suddenly complain: "Why are my rear lights...?"

Bertil wrote:

So that the occupants will eventually suddenly complain: "Why are my rear lights...?"

I've also noticed the emergency functions on the W203 quite intensely. When a tail light fails, the brake light dims, but with an audible frequency of around 1 kHz. It seems electromagnetic compatibility isn't an issue there.

I'm just going to say that, in my opinion, the pulsing in some vehicles comes from the electronic design of the circuit board. Lear often uses the Atmega8 (as an energy-saving type) in many components. This only has 2 hardware PWM outputs. If you want to use other outputs for PWM, you have to control the PWM via software.
The CPU of the headlight control unit (e.g., an Atmega8, which costs only a few cents and is found in many toasters) has very limited processing capabilities --> it needs to handle communication with the CAN controller, manage the inputs and outputs, and control the timing of everything. This quickly leads to conflicts between the PWM subroutine and the main routine. By using a lower PWM frequency, these conflicts can be mitigated from both a software and hardware perspective, placing the PWM process in a lower priority range.

Is this audible on a Mercedes-Benz?
Wow.

Even Opel manages to do it silently. The Vectra C only has P21W bulbs in the rear, so all four tail lights are dimmed, and definitely not with a resistor in series .

m;

dieselmartin wrote:

Is it audible on the Mercedes? Wow. Even Opel manages to do it silently. The Vectra C only has P21W bulbs in the rear, so all four tail lights are dimmed, and definitely not with a resistor in series .

Okay, I assume this is also because it's an emergency program. You can't hear it from inside the car, only when a tail light bulb has burned out and you open the trunk. So, it wasn't relevant for normal operation, but it was interesting. Also, the W203 probably only measures the current during operation and not the internal resistance. When the lights were turned on, the intact tail light came on for about 0.5 seconds before it went out again and was replaced by the "emergency light."