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2.1 RaËunanje srednje vrijednosti impulsa Ëija je<br />

perioda T 1<br />

kraÊa od periode signala T<br />

U sluËaju kada impuls ne popunjava periodu,<br />

tj. kada je vrijeme trajanja impulsa T 1<br />

kraÊe od<br />

vremena periode T (slika 2) , tada je srednja<br />

vrijednost takvog signala:<br />

2.1 Calculating the mean value of a pulse whose<br />

period T 1<br />

is shorter than the signal period T<br />

Where a pulse does not fill a period, i.e., if the<br />

duration T 1<br />

of a pulse is shorter than the time T of<br />

a period (Figure 2), the mean value of such a signal<br />

will be:<br />

(3)<br />

odnosno:<br />

or:<br />

(4)<br />

gdje je I sr<br />

(1) =<br />

periode T 1<br />

.<br />

I m<br />

2<br />

srednja vrijednost impulsa<br />

where is I sr<br />

(1) =<br />

period T 1<br />

.<br />

I m<br />

2<br />

the mean value of the pulse of<br />

Slika 2<br />

Unipolarni valni oblik ∑<br />

pilasti impulsi<br />

Figure 2<br />

Unipolar waveform ∑<br />

dented pulses<br />

I m<br />

i<br />

0 T 1<br />

t<br />

T<br />

Prema tome, srednja vrijednost impulsa Ëija je<br />

srednja vrijednost poznata moæe se lako izraËunati<br />

u sluËaju da je perioda T veÊa od trajanja impulsa<br />

T 1<br />

, tako da se poznata srednja vrijednost pomnoæi<br />

sa reduciranim vremenom T 1<br />

/T. Srednja vrijednost<br />

negativnog impulsa je negativna. Tako se npr.<br />

pomoÊu poluvodiËke diode (slika 3a) eliminira<br />

negativna poluperioda (slika 3b, c).<br />

Therefore, the mean value of a pulse whose mean<br />

value is known can be easily calculated if period<br />

T is greater than the duration T 1<br />

of a pulse by<br />

multiplying the known mean value with the reduced<br />

time T 1<br />

/T. The mean value of a negative pulse is<br />

negative. For example, that is how by means of a<br />

semi-conductor diode (Figure 3a) a negative halfperiod<br />

is eliminated (Figure 3b, c).<br />

KuzmanoviÊ, B., Baus, Z., FerkoviÊ, L., RaËunanje srednje i efektivne vrijednosti struje..., Energija, god. 56(2007), br. 3., str. 374∑387<br />

KuzmanoviÊ, B., Baus, Z., FerkoviÊ, L., Calculation of the Mean and Effective Current…, Energija, vol. 56(2007), No. 3, pp. 374∑387<br />

378

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