I think I am more likely to find the horn I normally tap, so I'm willing to use it knowing that I'll have a LOUD horn on the way. That was not my idea, but it is a good one. It may not be for you, but when fit hits the shan I won't find the loud horn if I rarely use it. The delay is welcome in that exchange.
Originally Posted by Warin
All true if the "constant current supply" is not using PWM. The bucks use PWM ... if you are using that too to get your "constant current" then the efficiency sould be similar.
A note on the horns...
On page 1 you said something like "One horn button - initial operation to the normal horn, after 1 second to the loud horn." Sorry but if someone wants the loud horn they want it now... not after any delay. In any emergency situation you want help NOW.
PS your definition .. well what happens if the resistance is not constant? EG a common light globe. Think about your Thévenin's and Norton's Theorems ! I stay away from definitions in most forums, they confuse rather than help?
There are some EMI regs that you may have to meet... FCC? Or some other gov agency.