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Block Diagram (wikipedia)

We left last time with some questions about the working core of NE555.
Time to answer.

As we get a digital output from pin 3 (quite Vcc or ground) what about its generation?

We saw the input pins by which we condition the IC, particularly pins 2 (trigger) and 6 (threshold); for now leave pin 5 (voltage control) away.
We will talk about it when we'll have fixed the fundamentals inside our mind.

These two lines go directly to comparators, 2-trigger to the inverting input of the below one while 6-threshold to the non inverting of the above; and as said the comparators give high or low out signal if the voltage input difference is positive or negative respectively.

And finally, outputs to the S-R F-F (Set Reset Flip-Flop).

...continue reading "NE555 – A brief look inside"

NE555 on breadboard

Maybe the most famous precision electronic timer of all times, NE555 was invented by Hans Camenzind (Switzerland) in 1970.

After more than 40 years it's still alive and healthy: born in the BJT's era now it is available in CMOS technology, even at low voltage (for more specific requirements) and in more than a package.

The interest about it never decreases, because of its simplicity and versatility.
And you'll find plenty of examples on the web with this IC involved.



By integrating both analogical and digital circuitry (very basic aspects) it is a bridge for the beginners to pass from discrete components to integrated ones with a good continuity level.

...continue reading "NE555"