On Tue, 23 Apr 2013 11:36:27 +0100, DavidR wrote:

wrote in message ....
On Mon, 22 Apr 2013 19:44:38 +0100
"Major Scott" wrote:
Surely they can design LED lights on cars to have a higher frequency PWM=
? Even =A3100K cars flicker dramatically, especially when filmed. It m=
akes them look really cheap. All it would take is a higher frequency PW=
M, or a smoothing capacitor?

They flicker for a reason. If they smoothed the current they might just as
well use DC direct from the battery. I don't know the technical reasons
why but

The effect relies on the persistance of the eyes to make it appear that the
average brightness is higher.

Easy enough to double the frequency of the flicker, then you wouldn't notice it. Remember 50Hz CRT monitors?

Smoothing at source would be less energy efficient.

I don't believe you. Switched mode power supplies are very cheap nowadays, especially compared with the cost of a car, especially a £100K car which has the same problem.

You can get a very smooth DC voltage of any level out of one - just look at your PC power supply then think of a smaller version of it. There are in fact smaller versions of it on your motherboard changing 12 volts to the CPU voltage (which is in fact variable).

Agreed the effect is not pleasant. It would help if they could introduce
softer start for indicators

I prefer them to go on and off suddenly. The only problem I have is flickery tail lights.

and brake light dimming when conditions suggest a slow moving queue.

I don't agree with different brightnesses of brakes. We already have two brightnesses of red - tail and brake. Adding more would just lead to confusion, you would wonder if it was a tail or a brake.

--
"It is generally inadvisable to eject directly over the area you just bombed." - U.S. Air Force Pilot training manual