I am currently toying around with electronics and read Make:Electronics which is a very fun book.
In one experiment (19) I came to a deviation in behaviour of my circuit compared to the expected behaviour described in the book.
The following image contains two different 555 IC configurations (sorry for the schematic, I am a beginner)
The left one is a bistable configuration (with the omitted reset button) that is responsible to start the left 555 IC and therefore trigger the red LED.
The right one is in an astable configuration that, when powered, causes the green LED to periodically blink. The period is very long and implemented with a 470k resistor combined with a 3.3microfarad capacitor.
Both parts are basically copied from the book and behave predictably when executed independent of each other (by removing the one and then the other IC).
The above configuration however has some oddity for me, which I do not understand.
When powered, the green LED begins their cycle but when the green LED is off and I start the bistable 555 IC, the red LED is turned on. And this is the part I do not get. I would expect that the red LED stays on indefinitely but the next time the astable IC turns the green LED back on, the red one is turned off. And even vice versa, when the green LED is on, pressing the push button on the bistable one, turns the green LED off and the red on.
My assumption is some voltage drop but I do not see what could cause that. I suspected the discharge pin 7 but since there is a 10k resistor between VCC and pin 7 I am not sure what actually happens.
Any hint would be wonderful.