odd AC capacitors

Cydrome Leader wrote: ==================

** Not one likely.

DC offset on the AC supply is not common and rarely troublesome. It is only caused by an asymmetrical load on the half waves.

The effect is to make toroidal transformers audibly hum a little. The fix involves a pair of diodes and regular electros.

..... Phil

Might that be why some dimmable LEDs make that bloody whine? They use a

120 (220 in other places) switcher to bring the AC down to 12VDC for the full brightness, and adjust it downwards as the dimmer (LED compatible dimmer) is reduced. So the small transformer may be whining? Perhaps I'll seal it in RTV silicon and see if that helps.

I also noticed regular dimmers doing similar noise.

John :-#)#

I put four 12 mF caps in parallel here as DC output blocks,

to keep any h-bridge offset from messing up the transformer.

I used regular polarized 6v 'lytics, as I didn't expect much voltage. Cranked in about a volt of imbalance just to be legal.

mandag den 25. oktober 2021 kl. 02.58.22 UTC+2 skrev snipped-for-privacy@highlandsniptechnology.com:

ebay special,

$67 for a bare PCB? Very special.....

Arie

snipped-for-privacy@fonz.dk wrote: ====================

** ROTFL - wot a hoot.

Bulgarian * audiophool * bait par excellence !!!!.

** " I though I could trust those Bulgarian trolls ... "

...... Phil

--------------------------------

** Giant HUH ??

Try learning to read.

..... Phil

Rod Elliott has a write up here ...

piglet

It says: "Here I'm offering you a bare PCB for DC Blocker - v.3. It is a successor of the very successful second version of the unit.".

As not usual on this site, the main picture does not match the actual object. Further down, the bare PCB is shown.

A.

Aha, scrolling even further down below the pictures: "What the buyer will receive: The package will contain 1 pcs. FULLY ASSEMBLED and tested DC trap/blocker/filter for toroidal transformers (toroids)."

You're right.

A.

Arie de Muijnck wrote: --------------------------------

** The writer is Bulgarian - so bad at English expression. So are you. Here "bare" = no case supplied.

Pays to read the whole of something before pronouncing on it.

...... Phil

well, someone felt the need to have those caps made. I wonder if they're really just two anode foils rolled together. I wonder how they form the oxide coatings as well. Usually the first step is done outside the capacitor, and then the final oxide coating is done after the cap is rolled.