Steering wheel interferes the bridge amplifier

Discussion in 'General Electronics Chat' started by ilker06, Jul 9, 2018.

  1. ilker06

    Thread Starter New Member

    Jun 26, 2018
    Hi masters,

    I made a siren and a bridge amplifier for my car and the result is almost perfect except the above mentioned problem.
    When the car is running but not moving, as soon as I start to turn the steering wheel a little buzzing sound comes from the horn speaker.
    When I leave the steering wheel it stops. Probably electric assisted steering wheel system is the reason of the matter.
    I put a 2200 uF between positive and negative terminal of the amplifier and siren. It reduced a little bit but did not remove the buzzing. I put a 1N4007 between positive and negative terminal, the result is the same.
    I don't know do I have to use a coaxial screened cable form amplifier to horn speaker. Can audio output cable catch this kind of noises ?
    What kind of filter do you advice to stop this buzzing ?

    Thanks in advance.
  2. Hymie

    Active Member

    Mar 30, 2018
    I would recommend you try something as simple as the attached circuit, supplying power to your amp & siren.

    Diode D1 must be rated for the load current, capacitor C1 could be your 2,200uF electrolytic with C2 being a 100nF capacitor.

    Increasing the value of C1 will reduce the 12V line noise further.
  3. crutschow


    Mar 14, 2008
    If that doesn't work adequately, you can also try adding a small resistance in series with the diode, perhaps a few ohms, depending upon the current drawn by the siren.