Return to KLUBNL.PL main page

[Top] [All Lists]

LF: Another kind of LF-PA?

To: [email protected]
Subject: LF: Another kind of LF-PA?
From: haagrimbergen <[email protected]>
Date: Wed, 21 Jul 2004 14:45:24 +0200
Reply-to: [email protected]
Sender: [email protected]
Dear OM's
I was pondering over using the horizontal TV-deflection system as a PA for LF. By stretching the flyback time to 50 percent of the period, using a push-pull stage with two identical circuits and then subtracting both outputs from each other should give a nearly perfect sine-output.
 So I breadboarded a test circuit with two IRF730 FET's and after ample experiments it resulted in over 50 W RF on 136 kHz in a 50 ohm dummyload with 70 V dc input. Efficiency proved to be over 90 percent. Vdrain was abt 260 V peak and Isource of each FET was abt 2.2 A peak, both well within spec.
 Measured with a spectrum-analyser: even harmonics were more than 40 dB and 3rd harmonic was 23 dB below fundamental.
 Is this contraption already known yet as an LF-PA ??
 If so, then:
                 1) What class of operation is it ?
                 2) I re-invented the wheel.
   Thanks in advance for your comments
        73 frm Harry, PA0LQ since 1946.
<Prev in Thread] Current Thread [Next in Thread>
  • LF: Another kind of LF-PA?, haagrimbergen <=