It should be the same as the Channel A output. Start with a high frequency, 20 kHz, and measure output voltage CB-V peak to peak from the scope screen.Repeat Steps 2 and 3, as in part A, to obtain the oscilloscope.Set up the RL circuit as shown in Figure 3 on your solderless breadboard, with the component values R1 = 1 kΩ, L = 20 mH.This gives the cut-off (roll-off) frequency for the constructed low-pass RC filter.įigure 6. Compute 70% of V p-p and obtain the frequency at which this happens on the oscilloscope. Increase the frequency of Channel A in small increments until the peak-to-peak voltage of Channel B is roughly 0.7 times the peak-to-peak voltage for Channel A. It should be the same as the channel A output. Start with a low frequency, 50 Hz, and measure output voltage CB-V peak to peak from the scope screen.Also, from the Meas CA menu, select A-B Phase. From the Meas CA drop-down menu, select P-P under CA-V and do the same for CB. Adjust the time base until you have approximately two cycles of the sine wave on the display grid.
From the Trigger drop-down menu, select CA-V and Auto Level. From the ALICE Curves drop-down menu, select CA-V and CB-V for display.From the AWG B Mode drop-down menu, select the Hi-Z mode. From the AWG A Shape drop-down menu, select Sine. From the AWG A Mode drop-down menu, select SVMI mode. Set the Channel A AWG min value to 0.5 V and max value to 4.5 V to apply a 4 V p-p sine wave centered on 2.5 V as the input voltage to the circuit.Set up the RC circuit as shown in Figure 2 on your solderless breadboard, with the component values R1 = 1 kΩ, C1 = 1 μF.The 70% frequency is called cut-off frequency, roll-offįigure 5. A frequency is considered passed if its magnitude (voltage amplitude) is within 70% or 1/√2 of the maximum amplitude passed and rejected otherwise. They don’t absolutely pass some frequencies and absolutely reject others. Filters, like most things, aren’t perfect. Conversely, if it passes low frequencies and rejects high ones, it is a low-pass filter. If a filter passes high frequencies and rejects low frequencies, then it is a high-pass filter. This selection and rejection of frequencies is called filtering, and a circuit that does this is called a filter. These characteristics can be used to select or reject certain frequencies of an input signal. The impedance of an inductor is proportional to frequency and the impedance of a capacitor is inversely proportional to frequency. The impedance of capacitors and inductors are frequency dependent. The output level of the passive filters is always less than the input since they have no signal gain. Passive filters consist of passive components, such as resistors, capacitors, and inductors, that have no amplifying elements, such as op amps, transistors, etc. The objective of this lab activity is to study the characteristics of passive filters by obtaining the frequency response of a low-pass RC filter and high-pass RL filter.