ac/dc and coupling caps (newb question)

[buschfsu]

sanity check.

audio rides on low voltage AC

tubes are powered by high voltage DC (for bias voltage and such)

coupling caps block dc from going from one gain stage to the next but allow AC to pass audio (current with vairable frequency information??)

AC and DC can live together on the same piece of copper???

 

[northsiderap]

From my non-accredited standpoint, yes.

DC is a nice even potential between two points. AC is pushing and pulling.

I've found cool explainations off of Google on how the electrons are acting in a capacitor when faced with both DC and AC...

 

[pstamler]

[quote author="buschfsu"]tubes are powered by high voltage DC (for bias voltage and such)[/quote]

And plate voltage.

coupling caps block dc from going from one gain stage to the next but allow AC to pass audio (current with vairable frequency information??)

AC and DC can live together on the same piece of copper???

Sure. Picture the plate of a tube. It's sitting at, say, 150V. With no signal, it stays there as long as the gadget is turned on. When you run signal into the grid, the voltage on the plate wiggles up and down, with its lowest dip at 140V and its highest peak at 160V. That can be thought of as an AC signal of 20V peak-to-peak, superimposed on a DC voltage of 150V. Run that through a coupling cap, and (somewhat oversimplifying) the AC passes but the DC doesn't, and you just get AC.

Peace,
Paul

 

[The Kid]

AC and DC can live together on the same piece of copper???

I sincerely hope so, or the universe as we know it is in big trouble! :grin: