Re: a little help please

by **Ivan** Sat Feb 14, 2015 1:03 pm

Hi David,
I am glad I could help you.

BR from Ivan OK1SIP

by m6ehi Fri Feb 13, 2015 7:34 pm

Thanks Ivan,
nice and easy to understand, it seems odd to me that I have never seen that principle explained anywhere else including the books I have read.
maybe someone should write a new book with all the basics explained in simple terms like your answer.

thanks again,
Best regards
david
M0HTD

by **Ivan** Fri Feb 13, 2015 8:49 am

Hi David,
The "total swing" means peak-to-peak voltage 10V. Taken from zero level, there are +5V peaks and -5V peaks. RMS voltage is always related to the zero level, too. Then 5 x 0,70 = 3,5V

VBR from Ivan OK1SIP

by m6ehi Thu Feb 12, 2015 9:02 pm

Hi all,
can any one help me i have been reading the basic RF HF amps section and I got a little confused about this bit "With a 12 volt (13.8v) supply, the complete sine-wave peak-to-peak value can only vary from about 2-volts to about 13 volts, or a total swing of just over 10 volts. The RMS value of voltage is therefore 10 x 0.3535 = 3.5 volts"
I'm not really understanding something here [color:5191=600060]my guess at the rms voltage would have been 7.071v where did .3535 come from, I worked out its .7071x.7071x.7071 but why?????
any help appreciated.

[color:5191=600060][color:5191=600060][color:5191=600060][color:5191=600060]regards

[color:5191=600060][color:5191=600060][color:5191=600060][color:5191=600060][color:5191=600060]david

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