Question 493: AC fundamentals

Question

A transistor-oscillator using a resonant circuit with an inductor L (of negligible resistance) and a capacitor C in series produce oscillations of frequency $$f$$.  If L is doubled and C is changed to 4C, the frequency will be

Accepted Answer

We know that frequency of electrical oscillation in L.C. circuit is
f = $${1 \over {2\pi }}\sqrt {{1 \over {LC}}} $$
$$ 	herefore $$ $${{{f_1}} \over {{f_2}}} = {\left( {{{{L_2}{C_2}} \over {{L_1}{C_1}}}} ight)^{1/2}}$$
= $${\left( {{{2L 	imes 4C} \over {L 	imes C}}} ight)^{1/2}} = {\left( 8 ight)^{1/2}}$$
$$ 	herefore $$ $${{{f_1}} \over {{f_2}}} = 2\sqrt 2 $$
$$ \Rightarrow $$ $${{f_2} = {{{f_1}} \over {2\sqrt 2 }}}$$
$$ \Rightarrow $$ $${{f_2} = {f \over {2\sqrt 2 }}}$$ [As f
1
= f]

Answer

$$f/2$$

Answer

$$f/4$$

Answer

$$8f$$

Answer

$$f/2$$$$\sqrt 2 $$

AC fundamentals

A transistor-oscillator using a resonant circuit with an inductor L (of negligible resistance) and a capacitor C in series produce oscillations of frequency $f$. If L is doubled and C is changed to 4C, the frequency will be

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