555 Timer Problem

[Muhasaresa]

Hi everyone,

I have a slight problem understanding how part of the 555 timer works. I was using http://www.williamson-labs.com/pu-aa-555-timer_med.htm to help me and it is a very good diagram, but when the capacitor is in the process of charging up, why does current go through the trigger comparator only and not the threshold comparator as well?

I would greatly appreciate any help.

Muhasaresa

 

[Resqueline]

Current does not go through them (or in them); they are voltage comparators - changing states only for a moment at 1/3rd and 2/3rds of Vcc.
I don't find that animation to be a very good educational tool.

 

[duke37]

Very little current (negligible) goes in or out of the trigger comparator (pin 2) or the threshold comparator (pin 6).
Current comes from the positive supply through a resistor to the capacitor and pin 7. When the IC triggers, a transistor connects pin 7 to ground, discharging the capacitor.