Stefan At this sort of measured efficiency you would need very accurate calibrated measuring equipment. Figures of 96% are only possible with MAGIC FETS, RDS 0.0 and PA coils with wire resistance of
If I can get 80% for 400V on 500kHz using a pair of cheap and cheerful FETs cobbled together, 90% plus should be easy-enough by spending a bit of time and effort on their selection. A while back I
Hi Chris, Of course you are right about the measurement errors. Furthermore one has to think about if the driver "losses", so the power needed to drive the PA is included in the losses or if it is ig
Thank you for all that, Andy. May I suggest another thing we might look at? If we could measure the temperature of the FET case, perhaps we could deduce the dissipation, and therefore get a lower bou
Jim What you say is correct but it is virtually impossible to achieve the 90% plus efficiency claimed by some. The FET required in practice is not available and these high efficiencies are only theor
Anything above 70% is respectable especially if it cost nil for components and occassional use. de mal/g3kev -- Original Message -- From: [email protected] Andy Talbot To: rsgb_lf_group@blacksheep
Andy, I agree. I just had a look in experiment logbook. In 2002 I did build a 137kHz class E PA using a single IRF640 and got 255W output at 56V and 4.9A input (= 275W input), so efficiency was almos
Accurate LF Power measurement; Its all about calibration, accuracy, attention to detail, and thinking about the sources of all errors. If you think carefully about how to make measurements, even us
My LF 1 kW class E PA i using a single IRFP360 at > 96 % efficiency (at Z=R=50 Ohm of course). The driver is a ICL7667. The supply voltage is 80 VDC. That's not a dream ;-) Stefan/DK7FC Am 13.01.2011
Dear All, Stefan raises an interesting issue. I'm sure you are getting high efficiencies. But measuring it at these numbers close to 100% actually makes quite interesting demands on the accuracy of t
