hiker101
New Head-Fier
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- Jul 3, 2009
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Quote:
Umm....
This diagram violates conservation of energy.
A positive current cannot flow from -V to +V without the assistance of a battery or power supply- a source, in other words.
The power supplies in these amps span the rails, so the return current entirely skips the ground node in between.
Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif Ok, here's a little Electronics 101. Below is an illustration showing the two basic configurations. A is the passive ground configuration, B is the "active ground" configuration. The transistors represent a typical complimentary push-pull output stage. The red arrows represent conventional current flow (as opposed to electron current flow which would be in the opposite direction) for a positive going waveform. For the passive ground configuration, we can begin at the positive plate of the reservoir cap for the positive supply. From there it flows through the positive supply rail to the NPN output device. From there into the positive side of the driver. Then, from the negative side of the driver straight to and through the ground node and on to the negative plate of the positive supply rail's reservoir capacitor. In the active ground configuration, everything is the same up to the negative side of the driver. From there, instead of going straight to the ground node as it does in the passive ground case, it goes into the PNP output device of the ground amplifier. From there to the negative supply rail, where it doesn't stop, nor dribble onto the floor, nor evaporate into the air, but instead continues on to the negative plate of the negative supply rail's reservoir capacitor, then the positive plate of the same capacitor, and just as in the passive ground configuration, through the ground node and on to the positive supply rail's reservoir capacitor. So the active ground does not in any way divert load currents away from ground. Load currents go to ground with the active ground just as they do with the passive ground. The only difference is that the load currents take a more circuitous route to ground in the active ground configuration. Remember, current only flows through a closed loop. You can't have current start out someplace without it ultimately returning to that point. k |
Umm....
This diagram violates conservation of energy.
A positive current cannot flow from -V to +V without the assistance of a battery or power supply- a source, in other words.
The power supplies in these amps span the rails, so the return current entirely skips the ground node in between.