ReverseEMF +1 for great link.
I built exact same circuit without any modifications of capacitors or resistors, luckily even have 47K pot.
But I`m not getting duty cycle below 2ms.
50hz its holding perfectly tested with freqmeasure library.
duty cycle I`m taking via pulseIn() on HIGH
this is image for schematic from same website.
and attached is printscreen how its holding 50hz.
why I cant get short duty cycles ? resistors that I used are 20% tolerant but each measured with multimeter before putting on the board to be sure they all have right values.
calculations for duty cycle from that website.
The formula used is as follow:
t= 1.1RaC
Ra is the total of R4 and R3. So, the minimum pulse time when R4 is set to 0, is:
t= 1.1 x 8200 x 0.0000001
t= 0.902 ms
Note that this minimum pulse width time is longer than the trigger pulse to ensure that the pulse width generator doesn't constantly generate0.65ms pulses one after the other, but at a steady +- 50Hz interval.
WhenR4 is set to maximum, the time is
t= 1.1 x 18200x 0.0000001
t= 2.002 ms
