At 08:41 AM 2/11/02 -0600, Jim wrote:
>    "Alternatively, you can use the transistor as an
>     open collector driver, which is a class-C amplifier."
>
>I don't get it.
>
>Maybe I'm from the old school where Class C amps
>were only used for RF

Where does RF start, exactly?
Connect an antenna to it.

>(I can't recall a single audio
>application for a stage biased Class C and conduction
>angle for each cycle was significantly less than
>180 degrees) where the tank circuit provides for the
>balance of the re-creation of the waveform (tank, or
>LC resonant circuits being analogous to balance wheels
>or tuning forks of sorts).

Probably because they were worried about fidelity.
If you're driving a beeper, fidelity is right out the window.
You can drive a beeper as part of a resonant circuit, with the beeper
acting as a lossy tank capacitor.

>The "open coll." app above sounds more like the 2n2222 is
>being used as a switch, perhaps in PWM mode as in
>class D or the like.

You could do that too.

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