Quote from: lost_bro on May 25, 2014, 02:05:23 PM
...
I ask, what could be the *possible* relationship between the grounded threaded screw &
the copper foil windings within the transformer?
...

Hi Lost_bro,

The possible relationship is capacitance I think. This kind of mounting establishes a capacitive coupling
between the ground and the "inner world" of the pot core.

Gyula

Quote from: gyulasun on May 25, 2014, 02:56:31 PM
Hi Lost_bro,

The possible relationship is capacitance I think. This kind of mounting establishes a capacitive coupling
between the ground and the "inner world" of the pot core.

Gyula

Why not use a nylon or ceramic bolt and nut?  Or, is the capacitive coupling desirable in this application?

Bill

Quote from: avalon on May 25, 2014, 12:55:52 PM
Pay attention, man. I was referring to the dual-TL494 schematics posted by tarakan.

~A

Was starting to think I was asking the wrong person also ... ya I missed the schematic that was a couple days ago....


but regarding your scope and resonance, you said ti was a combination of frequencies... so if you change the yellow while the blue is making a spikey red... so you gain/lose spikeyness?[/size]


- Oh I see; I gave up after 10 minutes since there was only a small fraction left, I figured you weren't going to get there.


Are high amps good?

Dear Bill,

I do not know why the builder of the setup in question does not use non-metal bolt and nut. 
And whether a capacitive coupling is desirable in this application, I can only guess: yes... because
the builder may have found that advantageous.
Sorry.
(When I used pot cores in audio LC filters and one of the coils were ground-independent
in the circuit as the design had it, then the filter response changed a little when I positioned that single
pot core (with the ground independent coil in it) over the PCB ground plane. And I could not use ANY metal
bolts for fixing the cores because at the frequency involved any metal inserted ruined the high Q of the
coils, this increased insertion loss and decreased outside attenuation.

Gyula

Gyula:

Thank you for your answer.  I agree it would make sense to use non-metalic bolts but I guess we can assume then that he wants the effect by not using them.

A while back, my company made ceramic tuning tools for companies like Motorola for adjusting their pagers.  Metal would alter the results and plastic would deform and not work well over time so, they had us make ceramic tips for all of their trim pot designs of which I think there were like 5.  That was like 20 years ago....geeze, I am getting old.

Bill