I understand the first resistor filters out the dc offsets. I know that than some sort of voltage-divider is then used. I'm not sure what the hell it's there for though.
The capacitor blocks any DC component which could cause current to flow into or out of the transistor resistor biasing network or transistor base.
Also, the book says the transistor has to remain in a bias state. Which means, partially on?
When a transistor is used in a class A type amplifier, its biased so the collector voltage is approx half the supply voltage.
This is so the collector voltage can swing lower and higher than the half point voltage.
I don't understand the difference between a transistor which is partially on, and a transistor that is "fully" on
A partially on transistor is biased in the way I described.
A transistor used as a switch is either conducting, so that the collector voltage is close to 0V and all the supply voltage appears across the collector load or off, so no collector flows .
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