EJSS ammeter circular coil damping model with critical damping
http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html
source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip
author: lookang
author of EJSS 5.0 Francisco Esquembre

EJSS ammeter circular coil damping model with critical damping
http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html
source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip
author: lookang
author of EJSS 5.0 Francisco Esquembre

EJSS SHM model with resonance showing Amplitude vs frequency graphs, heavy damping (RED)
frequency ratio for better x azes values
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHMresonance01/SHMresonance01_Simulation.html
source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMresonance01.zip
source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMresonance.zip
author: lookang
author of EJSS 5.0 Francisco Esquembre

No damping
EJSS ammeter circular coil damping model with no damping http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHMcoil/SHMcoil_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip author: lookang author of EJSS 5.0 Francisco Esquembre 
Very light damping
EJSS ammeter circular coil damping model with very light damping http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHMcoil/SHMcoil_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip author: lookang author of EJSS 5.0 Francisco Esquembre 
Light damping
EJSS ammeter circular coil damping model with light damping http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHMcoil/SHMcoil_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip author: lookang author of EJSS 5.0 Francisco Esquembre 
Moderate damping
EJSS ammeter circular coil damping model with moderate damping http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHMcoil/SHMcoil_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip author: lookang author of EJSS 5.0 Francisco Esquembre 
Critical damping
EJSS ammeter circular coil damping model with critical damping http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHMcoil/SHMcoil_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip author: lookang author of EJSS 5.0 Francisco Esquembre 
Heavy damping
EJSS ammeter circular coil damping model with heavy damping http://weelookang.blogspot.sg/2014/03/ejssammeterangularcoildampingmodel.html https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHMcoil/SHMcoil_Simulation.html source: https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_SHMcoil.zip author: lookang author of EJSS 5.0 Francisco Esquembre 
Wikipedia
http://upload.wikimedia.org/wikipedia/commons/9/9c/AmpereometervintageHDR0h.jpg 
my edited version:
YJC note
The equations that model the motion of the car suspension spring mass system are:
$ F =  k (\theta  \theta_{0}) $
where $ F $ is the restoring elastic force exerted by the spring (in SI units: N), k is the spring constant (N·m−1), and $ \theta $ is the displacement from the equilibrium position $ \theta_{0} $ (in radians).
Thus, this model assumes the following ordinary differential equations:
$ \frac{\delta \theta }{\delta t} = \omega $
$ \frac{\delta \omega }{\delta t} = \frac{k}{m} (\theta  \theta_{0})  b\frac{\omega}{m} + $
where the terms
$ \frac{k}{m} (\theta  \theta_{0}) $ represents the restoring force component as a result of the coil spring extending and compressing.
$  b\frac{\omega}{m}$ represents the damping force component as a result of dampers retarding the car mass's motion.