Noisy automotive electronics environment question; car horn and BEMF

Thread Starter

Tonyr1084

Joined Sep 24, 2015
3,680
Car horns are probably just about the noisiest device on an automotive electrical circuit (back electromotive forces). What would happen to the horn if I were to install a snubber or a diode across the horn itself? Would that reduce the BEMF seen throughout the cars electrical system? Would the horn be louder or quieter? Or no change?

I'm on the road right now and can't do the experiment. In my hotel room and in my personal boredom (no work on Sundays) I ponder these things. What do you think would happen? No, this is not a test, just a pointless discussion. Maybe. Maybe not. Since the automotive electrical system is notoriously noisy, could a snubber on the horn reduce the amount of noise to all electronics? Well, I'm pretty certain it would reduce the electrical noise, but I wonder what that might do to the horn.
 

AlbertHall

Joined Jun 4, 2014
8,552
A snubber on the power feed to the horn would not affect the horn at all though it should reduce the electrical noise passed to the rest of the system. A didoe in this position will do very little/nothing. A diode across the actual horn coil cetainly would reduce the interference though it might change the frequency as the coil current would be maintained for longer.
 

bwilliams60

Joined Nov 18, 2012
1,198
I agree with Albert Hall in that it would not affect the horn at all. I also agree that it would reduce the back EMF but I really dont think there is all that much that would cause a problem in the overall system. For one thing, the wiring is usually run in a remote area away from everything else so as not to interfere with crucial system harnesses. Newer vehicles are using modules to control the horn and they will be diode protected at the module. I am sure that if there were a problem, the manufacturers would have thought of it by now. On the other hand, good on you to think outside the box.
 

Picbuster

Joined Dec 2, 2013
979
Car horns are probably just about the noisiest device on an automotive electrical circuit (back electromotive forces). What would happen to the horn if I were to install a snubber or a diode across the horn itself? Would that reduce the BEMF seen throughout the cars electrical system? Would the horn be louder or quieter? Or no change?

I'm on the road right now and can't do the experiment. In my hotel room and in my personal boredom (no work on Sundays) I ponder these things. What do you think would happen? No, this is not a test, just a pointless discussion. Maybe. Maybe not. Since the automotive electrical system is notoriously noisy, could a snubber on the horn reduce the amount of noise to all electronics? Well, I'm pretty certain it would reduce the electrical noise, but I wonder what that might do to the horn.
Any equipment/parts sold in Europe must comply to EEC norm (safety, immunity and radiation).
This is also applicable to cars, ships,plane +++++++++++
The combination of parts should also comply.
Each part, in a system, could be certified but the interactions between parts/equipment may not comply.

Result; building a car with certified equipment or parts will produce a not certified car unless the whole car is tested against the norm.

However; I don't know how the regulations in other parts of the world are.

So don't worry about electronic noise. It should be within the limits.

Picbuster
 
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