[Amps] Class A for AM

[KA5MIR]

Ok Gary,
  Thank you for that information.

Jeff/KA5MIR


On Wednesday 15 November 2006 17:53, Gary Schafer wrote:
> Hi Jeff,
> No that's not really the case. The plate current peaks have to go just as
> high in class A as they do in class B. The difference is that on the
> negative swing of grid drive the class A amplifier is always conducting
> where in the class B amp it does not conduct. That lowers the conduction
> time of the class B amp and improves its efficiency.
>
> On efficiency change % it depends on the starting point from which you
> look at it from. With the class B amp if you start at full power as the
> reference then the AM carrier efficiency would be down 50% from there. If
> you start at the carrier as a reference point then I guess you could say
> that the peak efficiency doubles or goes up by 100%. Most texts use full
> power out as the reference point and talk about how many % down things are
> from there.
>
> Kind of like the merchant marking prices up or marking them down. If you
> mark $1.00 down by 50% you get 50 cents. If you mark 50 cents up by 50%
> you get $1.00. To mark the 50 cents up you do not add to it but divide it
> by 50%. But if you just add 50% to 50 cents you then only get 75 cents.
> One is called "mark up" and the other is called "add on".
> All in how you work the numbers.
>
> 73
> Gary  K4FMX