Hi, i am using pwm output of 16f877 to control dc motor speed contol. the motor has a tacho output which has to be diplayed in the lcd display unit. the pwm period is 5 milli second. a TIP142 is used as driver transistor to the load( motor). the problem is i am unable to get stable output of tacho with the result the lcd display fluctuates by 5 to 7 counts. on the otherhand when i give varying dc voltage to the motor the tacho output is constant and the display is very stable. my question is
1.should i modify the driver ckt to convert the pulse width output to a dc voltage . or is there any way to get a stale dc tacho output.
1.should i modify the driver ckt to convert the pulse width output to a dc voltage . or is there any way to get a stale dc tacho output.