Quote:
Originally Posted by timmy
So in the end the 14at will be getting 6.3 v or around 8 v . I get the ma but not the voltage.
|
A series heater circuit is constant-current.
Parallel heater circuits are constant-voltage
So in a series string, the tubes' heaters have to be rated for a constant current. Therefore different voltages appear across different heaters, leading to oddball voltage designations (e.g., 2AF4, 3CB6, 5GH8, 19AU4, etc. etc.)
In a parallel circuit, the heaters all have the same voltage but some have different currents.