Alternate 555 layout

616

11:13:45

No one ever seems to post this despite how well known it is on the net. The difference is the output and discharge pins swap places: out charges and discharges the capacitor, while dis controls the output transistor with a pull-up.

Benefits:
0-100% duty cycle based on potentiometer, as opposed to 50-100% on traditional layout. One less resistor if you don't fix ctrl.

Problems:
~1.7V drop from Vcc on out pin means duty cycle doesn't exactly match pot setting. Problem gets more severe as Vcc reduces (near-unusable on 5V). Can be fixed by reducing ctrl voltage or sticking to higher Vcc (10V+).

published 10 years ago

Sine_eyed

10 years ago

That's good info Mamish, thank you. Ya know, I've looked through many websites for schematics, general electronic info and learning material, and there's plenty of 555 material to be found. And you're right- the majority of related stuff is all pretty standard, run of the mill kinda same ol' same ol'. Few and far between are the places that give you smart and insightful information. In my perusing, I've learned that the little 555's are much more nuanced and fickle than most really know..

matvid123456789

10 years ago

Bellissimo

Iswerambraj

10 years ago

I want to learn about all circuits

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