6. Automatic Fan Speed Control
Exact CFM requirements vary by application and end-use environment, but 60-70 CFM is typical
for the 120mm fan itself. For noise-sensitive applications, it is recommended that a thermally
sensitive fan speed control circuit be used to balance system-level thermal and acoustic
performance. This circuit typically senses the temperature of an internal heat sink and/or incoming
ambient air and adjusts the fan speed as necessary to keep power supply and system component
temperatures within specifications. Please refer to the fan speed control drawing below.
dBA
28
24
20
16
12
8
4
User's Manual / English
10% 20%30%40% 50% 60% 70%80%90%100%
7
RPM
2300
1800
1300
800
Load