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03/07/17 19:05
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#190758 - Relay noise, add a zener with the flywheel diode
Responding to: ???'s previous message
A significant part of relay noise is coming from contacts due
to the coil not charged/discharged fast enough because of the
surrounding magnetic field.

The typical flyweel diode is not an industry good practice because
it keeps running the coil from the magnetic field until it is "drained"
and the relay contacts are in a unsafe holding force during that period.

By adding a zener then the coil cut-off is far more fast because it
is running for a smaller part of the time until total cut-off.
So the contacts act more quickly and the noise is far less than
without the addded zener.

For a 12V coil relay a zener or 12V to 18V is a valid option, always
in series with the flywheel diode connected cathode to cathode
(or anode to anode).

List of 13 messages in thread
Relay noise            01/01/70 00:00      
   metal box            01/01/70 00:00      
      not possible            01/01/70 00:00      
   Are the output leads,inside the relay,...            01/01/70 00:00      
      FG Relays            01/01/70 00:00      
   can you ....            01/01/70 00:00      
      not piggies            01/01/70 00:00      
         LCD Shield            01/01/70 00:00      
            no scientific base            01/01/70 00:00      
   Avoid Relay noise addin a zener !            01/01/70 00:00      
      Source of noise            01/01/70 00:00      
         Relay noise, add a zener with the flywheel diode            01/01/70 00:00      
            Experimentation            01/01/70 00:00      

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