low pass filter for arduino PWM control to reach 10V Analog control

Arduino PWM control frequency is about 488Hz for pin 3,9,10,11..
and 977Hz for P5,6, in order to make it analog out put.
we selected a low pass RC filter where R=4.7K, C=3.3uF, which result a cut off frequency at about 10Hz...response time about 0.1-0.2 sec.

then we need to amplify it to 10V
http://arduino.cc/forum/index.php/topic,12135.0.html

2 ways are considered:
lpf 5v pwm and switch up tp 10V
http://www.3reef.com/forums/i-made/arduino-pwm-0-5v-0-10v-121705.html




using 10V source and MOSFET then lpf
http://www.reefcentral.com/forums/showthread.php?t=1995554

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