Author Topic: 555 discharge pin  (Read 742 times)

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Offline Chai

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555 discharge pin
« 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?  :-//
   
Quote
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/555_timer.html
 

Offline LukeW

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Re: 555 discharge pin
« Reply #1 on: March 17, 2016, 06:18:19 am »
The output driver section is inverting.
 

Offline Chai

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Re: 555 discharge pin
« Reply #2 on: March 17, 2016, 06:42:06 am »
Hah! Thanks :-+
 


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