Hey guys, im fairly new to electronics but im working on a project that involves controlling a 12v DC analog gauge. Normally the gauge would use a thermistor for the signal and as resistance increases the gauge decreases (ground state will max out the gauge). Ive set up a controller to PWM the gauge signal to ground instead of using a thermistor (100% duty cycle is full ground) running about 150hz. It actually works great with no extra circuits and I get gauge min at about 10% duty and gauge max at about 98% duty. The only issue is that I can hear it buzzing/humming very quietly and im a bit worried about any long term damage to the gauge internals. I did some research and found guys using a low pass filter so I tried a few cap/resistor combos and found that a 47ohm resistor tied into the PWM wire with a 1.0uF electrolytic cap (+ on resistor, - to ground) seems to cut down the humming the most (gauge output seems mostly unaffected). I just wanted to know if there is anything wrong with setting it up this way?
Thanks
Jason
Thanks
Jason