explanation of the 40106 ic

[bernte_one]

Is someone able to explain the function of the 40106 datailed, resistor by resistor and cap by cap
found this and it was very helpful
http://fluxmonkey.com/electronoize/40106Oscillator.htm

the reason is that i think about to make the pulsewidth and maybe the frequency variable by some additional pots
but i am still not able to explain all myself

my first target would be the oszi form pin 8 and 9



best regards

[Davor]

40106 is a Schmitt triggered inverter, which means it has a hysteresis, just like 555 has. So you turn it on, and cap is at 0V, so the gate is also at 0V and hence the output is at logical 1. Therefore resistor charges a cap, its voltage goes past Vss/2 and reaches the upper threshold, inverter goes to logical 0. Resistor discharges the cap etc.
The only problem with cmos Schmitt trigger is that the hysteresis voltage maybe anything in a quite wide range, so you can't really count on the exact frequency coming from this arrangement. For that reason it is often less painful to arrange a Schmitt trigger from some simple inverters and set the hysteresis to a known value.

[bernte_one]

Thanks Davor for answer,

and what did you suggest to change pulsewidth or frequency?

[Thomas]

[kt315]

I am feeling myself like a guy who takes files from forum and put them back. Sisyphus job.

[bernte_one]

I am feeling myself like a guy who takes files from forum and put them back. Sisyphus job.
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yes it seems so, but you make it very good

to you and thomas many thanks

[Thomas]

I am feeling myself like a guy who takes files from forum and put them back. Sisyphus job.
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Thanks from all us with short memories.

[kt315]

I have not 40106, found only 74HC14.

a signal on 8 pin. o-scope scale 50us/div and 2V/div.

[kt315]

0,5us/div. i decrease R7 to 107k getting 600 Hz

[Teleno]

Thanks Davor for answer,

and what did you suggest to change pulsewidth or frequency?

The same you do on a 555, use asymmetric resistive paths split by a diode.