# 0.2 Operational amplifiers and signal conditioning  (Page 4/5)

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The resultant signal should be an 800 mV sine wave with minimal offset.

Using the inverting gain circuit shown in Figure 8, amplify the output of the differential amplifier circuitby an additional factor of ten. This can be done with another op-amp and a 10 k ohm resistor and a 30 k ohm resistor. Theresultant output signal should have a mean of zero and amplitude of ~2.4 V. Adjust the potentiometer to remove any offset.

## Part 7: low-pass filtering

A low pass filter can be used to attenuate high-frequency noise in an analog signal and to minimize the portion of the signal that will be aliased. Later in this lab, youwill see a demonstration of the damaging effects of aliasing.

## 7.1 build an active low-pass filter

• Build the first-order filter shown in Figure 9 with R1 = R2 = 10 k ohm and C2 = 0.1 micro F. First order filters are so-called becausetheir dynamics are modeled by first-order differential equations.
• Connect the output of the circuit to Channel 1 on your DAQ system.
• The filter’s time constant is equal to R2C2. Calculate values for the cut-off frequency and the time constant.

## 7.3 modifying existing vi to measure magnitude ratio

By measuring the magnitude of the input and output of a filter, you can determine the how much the filterattenuates the signal.

• Delete the Amplitude and Frequency constants from the Block Diagram.
• Hold Ctrl as you drag the Tone Measurements icon to make a copy.
• Place a Split Signals icon to the left of the Tone icons.
• Place a Divide function to the right of the Tone icons.
• Create a numeric indicator at the x/y output terminal of the Divide function.
• Rename the numeric indicator Magnitude Ratio. (The Magnitude Ratio represents the output amplitude divided by the inputamplitude.)
• Wire the Block Diagram as shown in Figure 10.
• Save the VI.

## 7.2 testing a filter

We expect that the filter will allow frequencies below the cut-off frequency to "pass", and willattenuate signals at higher frequencies. The Magnitude Ratio will be recorded as the output magnitude divided by the inputmagnitude.

• Connect the signal going into your filter to Channel 0 of module 1 of the SCXI.
• Connect the signal coming out of your filter to Channel 1 of module 1 of the SCXI.
• Input a 1 V sine wave with zero offset into the low-pass filter circuit.
• Starting with a frequency of about 10 Hz, slowly increase the frequency of the input signal. What happens to the outputsignal?
• Increase frequencies to 2 kHz.
• Using the table below, determine the magnitude ratio at several frequencies.

Table 1: Magnitude Ratio Data for First-Order Low-Pass Filter (Active)

 frequency (Hz) Input magnitude (V) Output magnitude (V) Magnitude ratio 10 1V 18 1V 32 1V 58 1V 110 1V 190 1V 340 1V 620 1V 1100 1V 2000 1V
• Using Excel, plot the following two sets of data on a single log-log chart.
• Calculated magnitude ratio vs. frequency.
• Measured magnitude ratio vs. frequency

Do the magnitude ratio and phase difference between the input and output behave as you would expect?

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research.net
kanaga
Introduction about quantum dots in nanotechnology
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nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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Daniel
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Maciej
Abigail
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Anassong
Do somebody tell me a best nano engineering book for beginners?
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NANO
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are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
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Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
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Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
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Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
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Porter
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Yasmin
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Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
how did you get the value of 2000N.What calculations are needed to arrive at it
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