[Amps] Grounded B+ amplifier

[Ian White, G3SEK]

Steve Thompson wrote:
>On Thursday 26 February 2004 17:33, Bill Turner wrote:
>> Years ago I recall reading about an amplifier where the B+ supply was
>> grounded and the cathode was "hot" with the B- supply.  I'm wondering if
>> that might have some advantages for high power amplifiers.
>>
>> Specifically, the pi-network output could be simplified by eliminating
>> the plate choke.  Here's how the output would look:
>>
>> http://www.dslextreme.com/users/teeaye/B+.jpg
>>
>> Believe it or not, this is a pi-network output circuit, just redrawn.
>> The same component values would be used as with a conventional circuit.

>Doesn't it do a lovely job of offering an alternative insight into how 
>a pi network matches between the antenna and plate. The load control is 
>the lower capacitor and provides a variable 'tap' up and down the tuned 
>circuit.
>

Yes, I liked that too - although turning the pi-tank around seems to 
have lost its lowpass filter properties.

Grounded anode is fun to think about, but I'd hate to have to build one. 
For every problem it solves, ten new ones appear!


-- 
73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)

http://www.ifwtech.co.uk/g3sek