Noise Reduction Techniques
2-11
4.4
Voltage Regulator Noise
This type of interference is characterized by erratic popping noises which change only slightly with
changes in engine speed. The noise is generated by arcing in the vibrating breaker contacts of the
voltage regulator. It can be suppressed by connecting a 0.5 µF coaxial capacitor (Motorola Part No.
0882571B01) in the battery and armature leads of the voltage regulator (see Figure 2-8 Voltage
Regulator Noise Suppression).
4.5
Hood and Trunk Lid Noise
This type of noise is characterized by irregular popping sounds. It is caused by friction in poorly
bonded automobile hoods or trunk lids. This friction causes static electricity to build up until arcing
occurs. This type of noise is suppressed using a Motorola Hood Wipers and Mounting Hardware Kit
(part of TLN8845_ or TLN6252_ Noise Reduction Kits) which provides electrical bonding of the
hood or trunk to the vehicle body while permitting them to be opened.
CAUTION: Disconnect the battery ground terminal before attempting to connect components
to the voltage regulator.
Figure 2-8 Voltage Regulator Noise Suppression
!
Step 1.
Mount Capacitor
(0.5µF Coaxial Type)
to vehicle chassis
using lockwasher and
self-tapping screw.
Vehicle
Step 2.
Disconnect wire (dashed)
from battery post and
connect to capacitor
using lockwasher and nut.
Step 3.
Add lead from battery
post to capacitor using
lockwasher and nut.
Armature
A coaxial capacitor can
be added here, if required.
Battery
Post
FL0830265-O