Hello Frank,

first of all: the usage of a LED can be realized with a parallel resistor of 120Ω … 2.2kΩ.

The problem with my version of your experiment #2 is solved with a 0.1µF capacitor:

And the 0.1µF capacitor in experiment #1 was worthful; the first 2…4 times the circuit worked o.k., but then the problem occured… so your version is well.

Best regards,


  • This reply was modified 2 years ago by Guenther.