Suppose you want to make a parallel LC circuit fig 1106 with

Suppose you want to make a parallel LC circuit (fig. 1.106) with L = 100 pH and a resonant frequency of 1.0 MHz. What capacitor value should you use? You\'ve chosen that capacitor and want to verify the resonant frequency, so you attach the scope probe in \"1X\" mode to monitor V_out as you sweep a drive frequency at V_in. Where will you find the resonance? (The photograph shows the BNC connector for one of our probes to give you its specs.) Same question, but the scope probe is in \"10X\" mode.

Solution

A) To calculate the capacitance in the LC circuit:-

First of all we must know the very basic derivation for the resonance frequency which is

= 1/LC (1)

To calculate the freqency in Hertz we can resolve our above expression in the form:

= 1/(2*LC) (2)

We are given with the values of inductance and the frequency, i.e:

L=100 mH = 10^-4H and f or =1MHz = 10^6Hz

So we need to calculate “C” and solving eq (2) further we get following final expression:-

C=1/(2 *)^2)*L (3)

Putting the given values in eq3, we get:-

C=1/(2*10^6)^2)*10^-4

which gives: C= 2.5*10^-10C

Value of capacitance

B) To veify frequency, using FM sweep generator in X-Y mode is the best technique. Use scope X axis sweep to CH1 and Ch1 out to FM in . Connect the CH1 to X axis on scope and connect the CH2 as signal currents over R after this set the values for time and voltage via the nopes provided over the scope and the scope will show the frequency resonance.