EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Chai on March 17, 2016, 04:51:47 am
-
I'm confused why a LOW on the output pin 3 would drive the discharge pin 7 to ground. I thought a low coming from the flipflop/output connected to the base of an NPN would turn off the transistor and disconnect pin 7 from ground. What am I missing here? :-//
Discharge, The discharge pin is connected directly to the Collector of an internal NPN transistor which is used to “discharge” the timing capacitor to ground when the output at pin 3 switches “LOW”.
(http://www.electronics-tutorials.ws/waveforms/tim37.gif)
http://www.electronics-tutorials.ws/waveforms/555_timer.html (http://www.electronics-tutorials.ws/waveforms/555_timer.html)
-
The output driver section is inverting.
-
Hah! Thanks :-+