Electronics > Beginners
Triangular wave on ring oscilator
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Wimberleytech:

--- Quote from: Belrmar on May 29, 2018, 02:53:49 pm ---ook lets start, the oscilloscope is a promax od-416, i am using a 10x probe(oscilloscope does not have compensation for that but i can live with it) , the part number is cd40106BE, supply voltage is 12v from a linear regulator powered by a switching one.all the caps are 22nf. oscilloscope set 1uS and 2v per division (having on account the 10x)

images here: https://imgur.com/a/wEfyz6C

--- End quote ---
Great!

Your triangle waveform ramp rate is 6 volts per microsecond (deltaV/deltaT = 6e6)

I = C x deltaV/deltaT
I = 22e-9 x 6e6 = 132 mA    The 40106 cannot deliver that much current.

Therefore, I think your capacitor is not 22nF.

Please show us a picture of the capacitor markings (all three side by side).

Why are traces different???  Assuming the caps are all the same, consider this possibility.  If you removed the caps from a tape carrier (often they come this way), I have found that there is glue reside on the terminals.  This residue can insulate the wire and thus not make a connection.  Make sure the terminals of the caps are clean and making good contact.
Belrmar:

--- Quote from: Wimberleytech on May 29, 2018, 03:19:45 pm ---
Therefore, I think your capacitor is not 22nF.




--- End quote ---
agreed i made a bit of a fool of myself, the markings where 221 not 223, i should use my glasses more often
Wimberleytech:

--- Quote from: Belrmar on May 29, 2018, 03:29:39 pm ---
--- Quote from: Wimberleytech on May 29, 2018, 03:19:45 pm ---
Therefore, I think your capacitor is not 22nF.




--- End quote ---
agreed i made a bit of a fool of myself, the markings where 221 not 223, i should use my glasses more often

--- End quote ---

Ahaaa!!  No problem.  I wear 3x readers and sometimes even that is not enough!!

Still does not answer why one of the outputs is a square wave.
Belrmar:
Just used another of the ic's form my batch and this one is giving me 3 square waves.... i am a bit confused, might be some esd dmg that led to a damaged output stage? a bad puppy on the batch... no idea tbh
Brumby:
With 3 caps on 3 stages, I would expect 3 triangular waveforms.  3 square waves doesn't make sense.  I would be really checking the contacts of those caps.

Is it still running at the same (or similar) frequency with 3 square waves?
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