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Vavg, Vrms

imlookingforsomehelp

Oct 18, 2010
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Oct 18, 2010
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Its known :triangular ,rectangular ,Sinusoidal:

For tringulat :
RMS =vmax/sqrt(3)
vavg =Vmax/2

Sinusoidal:
RMs=Umax/sqr2(2)
vavg =0?

No idea how it is for rectanglular.

And vavg can be negative? I mean with the (-) symbol? Because the oscyloscope said vavg with the - symbol for every waveform. Its oscyloscppe bad or it can be possible? Anyway i have to count the RMS and vavg manually.
 

imlookingforsomehelp

Oct 18, 2010
9
Joined
Oct 18, 2010
Messages
9
New task :|

Instruction

COunt with the function generator decade resistor and oscyloscope.
Loads R0(big R little 0) of the decade resistor serves as the load for funcion generator
Set the sinusoid on vpp=5 and f=5khz. Measure the dependence betwen vpp and R0. Put the results in tab:

It looks :
rcsrys.jpg


The full question is :
Count I and active power(y) from generator with diffrent loads (r)
estimate the threshold for I and power that can be downloaded from the generator without changing its voltage,


Wherewhere x means : 4,96 V
y - active power ( or downloading power. not sure how to translate it)
 
Last edited:

Resqueline

Jul 31, 2009
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Jul 31, 2009
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Any waveform swinging around zero has a Vavg of zero. Obviously your triangular wave had its bottom peak at ground potential to make Vavg=Vmax/2.
To find the reason behind Vrms=Umax/sqr2(2) you'll have to integrate a sine function from 0 to 180 degrees. That was hard enough for me to do at school 20-25 years ago.
Doing the same for a square and a triangle it can be done using simple area calculations.
Frequency is the inverse of the time for a full cycle/period. If t =199ns then f=1/0.199=5.025MHz.
I can't say anything about the 'scope with the information given.

New task: apply Ohms law 17 times.
 

imlookingforsomehelp

Oct 18, 2010
9
Joined
Oct 18, 2010
Messages
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Thanks for the answer.

For rectangular i have a parrern which is
5lcvfd.jpg


but not sure how to replace it with Umax and T, because there is also needed t1 and U2.
U1 means Umax i think. Im really hopeless at electronics.

And for the frequency, shouldnt it be 5.025KHz? Could you please write full calculations?
 

imlookingforsomehelp

Oct 18, 2010
9
Joined
Oct 18, 2010
Messages
9
Are you good with half and full -wave rectification. I need to know something theoretically

U1. voltage that goes through half wave rectification.
u2 - through full wave rectification
U1s - U1 stabilised by RC
U2s - U2 stabilised by Rc
Namely: Compare counted vavg values of U1 nad U1 with measured solid components U1s U2s.
Explain why the variable components appeared
 
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