I'm interested in analog pwm circuits, and present this idea I found
on bowden's hobby circuits.

http://www.bowdenshobbycircuits.info/buck.htm

I am curious about which component
sets frequency, and if a pot could sub for the two resisters that
set the pulse-width/ratio.

Finally, is the output from the CD4069 a square or sawtooth output?

 

Hello,

Have a look at this thread:
https://forum.allaboutcircuits.com/threads/project-simple-pwm-circuit.9016/

Bertus

 

Hello,

Have a look at this thread:
https://forum.allaboutcircuits.com/threads/project-simple-pwm-circuit.9016/

Bertus

I don't have any CD4093 parts, but I have mm74hc132... Except for pinouts and voltage, maybe combined a with
logic mosfet?

 

sawtooth output

 

The output from the CD4069 is a Square wave..

 

I don't see a pull down resistor on the gate, does the 4069 hex inverter supply a push/pull signal to the gate,
acting a a "gate-driver"?

 

Not being used like that it's not going to be a Square wave

It be sawtooth output

The CD4093 is the way to go.

I've looked at a lot of these with a scope and the CD4069 driving a gate doesn't look square wave at all.

It ramps up then falls down, The CD4093 is more like snap on snap off.
The CD4069 is push pull

 

I'm interested in analog pwm circuits, and present this idea I found
on bowden's hobby circuits.

Where's the PWM? You can change frequency pretty easily, but not duty cycle.

A two inverter oscillator is a crap shoot. You could tweak frequency to the point where it stops oscillating.

 

Any Schmitt inverter will work:

From: https://www.dos4ever.com/flyback/flyback.html#ind2



Or more simply:


Just add steering diodes as is done for 555's too.
Source:
http://www.fairchildsemi.com/an/AN/AN-118.pdf (Now ON Semi ) Link is probably dead.

 

I have mm74hc132... Except for pinouts and voltage, maybe combined a with
logic mosfet?

That will work. Post #9 has a suitable circuit.