Class C?
Class C is just for RF power, where the amp is driving a high-Q RLC tank circuit tuned to the fundamental. The tank circuit removes the harmonics.
--Russell
Class C is just for RF power, where the amp is driving a high-Q RLC tank circuit tuned to the fundamental. The tank circuit removes the harmonics.
--Russell
Class A + Class C, that's exactly how I would describe it.
In simulations you can clearly see that the output transistors do not conduct for a short period of time. That is why the principle is also called 'current dumping'.
In simulations you can clearly see that the output transistors do not conduct for a short period of time. That is why the principle is also called 'current dumping'.
Note that the goal of the class A stage is not, as often said, to fill the non-conduction area of the class C transistors.
In fact the class C stage provides the heavy current that the class stage can't. All this is under the control of a bridge and feedback, the expected result being that amplifier has a constant output impedance during a full cycle.
In fact the class C stage provides the heavy current that the class stage can't. All this is under the control of a bridge and feedback, the expected result being that amplifier has a constant output impedance during a full cycle.
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It is both, of course. Otherwise nothing would fill in the class C gap. Very instructive to look at the signal at the base of Tr10.
Hi
The Nak 620 output stage is simply a diamond where each of the four positions is a Darlington, although everything is discreet. This provides a single node input.
Personally, I disagree with Self's definition of "class-B" as there is a small overlap of conduction nd each half of the output stage is therefore 'n' for more than 180-degrees of the signal.
The Nak 620 output stage is simply a diamond where each of the four positions is a Darlington, although everything is discreet. This provides a single node input.
Personally, I disagree with Self's definition of "class-B" as there is a small overlap of conduction nd each half of the output stage is therefore 'n' for more than 180-degrees of the signal.
And what do you say about the Class B composite amplifier I presented ?Diagram on the latest charts .
Hi Stanislav1957
If you are referring to post-35, the upper case looks like class-B but the lower case does not. It is hard to tell exactly because at least for me the images do not expand very much and are hard to read. Your later post says the output devices idle at 2mA. Is that for the upper circuit?
Regarding the OP's Nak 620 being "current drive": I think this refers to the fact that like all diamond stages the output devices are turned 'on' by current sources. The default would be for the outputs to be turned on to the max and melt down the supply 😀 The only thing keeping this from happening is the input half of the diamond, provided their net BE voltage plus any RE voltage is less than what the output devices need to draw a lot of current.
If you are referring to post-35, the upper case looks like class-B but the lower case does not. It is hard to tell exactly because at least for me the images do not expand very much and are hard to read. Your later post says the output devices idle at 2mA. Is that for the upper circuit?
Regarding the OP's Nak 620 being "current drive": I think this refers to the fact that like all diamond stages the output devices are turned 'on' by current sources. The default would be for the outputs to be turned on to the max and melt down the supply 😀 The only thing keeping this from happening is the input half of the diamond, provided their net BE voltage plus any RE voltage is less than what the output devices need to draw a lot of current.
This is the same amplifier with a quiescent current of the output transistors of 1-3mA .Only the C11 capacitor circuit was turned off and that was it. My question was not on the mode, but on the amplifier circuit.