I followed the instructions in this video to make a fading LED circuit with a 555 timer:
...apparently loosely following the schematics here:
Note that the guy in the video uses different values for both resistors, the capacitor and the voltage source, and only one LED. And so do I. I use a 6V voltage (4xAA), a 130Ω resistor in series with two 3,4V LEDs in parallel, as the "high" resistor I use a potensiometer, and I use a 470µF capacitor. All is good and the circuit appears to work as it should.
1) Now, what I don't understand is the relationship between the capacitor and the high resistor (potensiometer). In the video instructions the guy said to use a 1000µF capacitor, which I tried. The comments below the video said a much smaller capacitor was all that was needed. I found that there seemed to be a linear-ish relationship between the capacitor and resistance. I could choose different values of capacitors, adjust the potensiometer, and the circuit behaved the same. Can someone explain this to me, and whether I'm tinkering with this in the right way?
2) Is the 130Ω resistor in series with the two LEDs (in parallel) an adequate value?
Thanks for your help.