Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Car rear indicators mean radiated emissions failure?

C

cupoftea

Advanced Member level 5
Joined
Jun 13, 2021
Messages
2,578
Helped
54
Reputation
108
Reaction score
115
Trophy points
63
Activity points
13,537
Hi,
Our contractor tells us we will fail radiated emissions because our rear indicators are ON/OFF, as you'd expect...meaning pulsed currents with steep di/dt edges, and this in the wiring all the way to the rear....antenna!
We dont want big filter inductors though, due to the LC ringing....so is he right?...will we fail it?
Can we use ferrite ebads instead of actual inductors.

I mean , there are loads of switching loads. Surely they dont all fail radiated EMC?

The last thing we want is an inrush limiter for every time the indicator gets flashed on. He also reckons it will interfere with the radio.?
 
Sort by date Sort by votes
Thanks, also, is our new 12A switching load going to give us any problems with radiated or conducted EMC?
LTspice and jpg attached.
 

Attachments

  • 12A switching load.zip
    1.5 KB · Views: 62
  • 12A switching loads.jpg
    12A switching loads.jpg
    108 KB · Views: 55
Upvote 0 Downvote
I guess you have a tool to measure, even approximately, the radiated electromagnetic waves. Otherwise, how will you know that a proposed solution is good?

As a simple solution may be to use a shielded TV cable from the controller output to the indicators. I think the voltage drop on the cable for 12A won't be high, but a real test has the last word.
 
Last edited:
Upvote 0 Downvote
Thanks, i believe crucial for us will be common mode chokes either end of the 2 metre cable of the "Mouse scarer"?
 
Upvote 0 Downvote
A car turn signal is Hz-range and any ringing EMI will be
tone-bursts on that "heartbeat". A spectrum analyzer might
"average it away" and pass the frequency mask. Figuring
that a wireball "ring note" is probably overwith in a microsecond
or ten, you'd see any spurs averaged down by a factor of
1E5 - 1E6? Unlike (say) the same line banged at 100kHz and
the ringing never quite getting done, before next edge.
 
Upvote 0 Downvote
EN radiation specs.
Also, the duty is 50% with period 10ms to 4sec repeatedly sweeping up and down. Willw e get flicker problems.?
 
Upvote 0 Downvote

LaTeX Commands Quick-Menu:

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top