I am building a very simple Series circuit with a better (9V), two LEDs (Red, 5mm) and a resistor (220Ω). See the circuit below.
Now, when I connect it all together, here is what happens:
1) (+), LED1, LED2, Resistor, (-): only LED1 lights up (that's the example on the picture)
2) (+), Resistor, LED1, LED2, (-): both LEDs light up
3) (+), LED1, Resistor, LED2, (-): both LEDs light up
So turns out, my circuit doesn't work when the resistor is connected directly to (-).
I have been told that in such simple circuit it doesn't matter where is the resistor.
Does anyone have an explanation to this?
Thank you! :)