Class E RF Amplifiers Explained - Circuit Design (Part 3)

Part 3 discusses the theory behind class E amplifiers and explains how they achieve very high efficiencies. It also shows the design equations that are used to determine circuits values for L and C and demonstrates how to use on-line tools to help with your designs.

[@jonhoyles714]

awesome 🙌 ❤ love it been watching your last videos on RF design and thanks for the education always nice 😊

[@afshintorkamanzadeh612]

for your education... very thank you .... 🙏🙏👏👏👏👏

[@yvanblom]

you made the most clear transition from Sokal's equations to practical implementatiion of a class E amplifier I ever saw... Thank you, and PLS send me your spreadsheet, as I am interested to experiment in the 80...10m amateur bands with low cost / good quality an good performance gear.

[@carminecampo2045]

Please send me an email and I will send you the spreadsheet. Regards

[@watthairston1483]

Thanks so much... Excellent!

[@davidmccarter982]

I think the RFC value is important. Too much and the choke will limit the current rise time. Too little and the choke will saturate during the transistor on time. Plus, a lot of current, 1.3A is flowing, so wire size is important. I’d like to see the actual circuit including a discussion on getting Hi Q with typical toroids available to the amateur.

[@MobiusHorizons]

How do you arrive at a saturation voltage of 0.5v for the IRF510? This has been something I have been very confused about when trying to choose a transistor for a Class E amplifier. If I understand correctly the saturation voltage is the Vds at which no more current flows for the selected Vgs. From the Ids chart it seems you would want Vgs as high as possible to reduce conduction losses, so Vgs = 10 and saturation looks like it happens at much higher than 0.5v (looks like 10v to me). Are you using the 4.5v curve instead? If so, doesn't that leave a lot of efficiency on the table?

[@carminecampo2045]

In your post, you are describing the point where the transistor is conducting and fully turned on. This is not the Vds or Vce sat. voltage used in the class E calculation tool. For a MOSFET, It is actually VDSon which is determined by multiplying RDSon from the data sheet by the DC drain current (ID) at the desired output power level. Basically, you are applying ohms law E = I x R to determine the voltage that drops across the transistor when it is conducting. RF Man

[@MobiusHorizons]

@@carminecampo2045 Thank you very much!

[@carminecampo2045]

@@MobiusHorizons I hope my explanation cleared up a few things for you. RF Man