<< Chapter < Page Chapter >> Page >
In this lab, you will build several basic op-amp circuits to learn about the signal conditioning of sensor signals.


In this lab, you will build several basic op-amp circuits to learn about the signal conditioning of sensorsignals.

Teaching objectives

  • Understand how an op-amp works.
  • Learn about different types of op-amp circuits and their uses.
  • Gain practical experience in implementing op-amp circuits.
  • Build a voltage divider, an inverter, a differential amplifier, a gain circuit, and low-pass filter circuits.
  • Demonstrate the filtering capability of the low-pass filter and its use to prevent aliasing of sampled data.

Preliminary reading

Figliola and Beasley

Analog Signal Conditioning: 211-226 (Sections 6.6-6.8)

Component identification

In this lab, we will be using several types of electronic components: resistors, capacitors, trim potentiometers,and op-amps.


Resistors come in a wide range of resistances. For op-amp circuits, values in the range of 10 k ohm to 250 k ohmwork best. For this lab, we will use primarily 10 k ohm and 100 k ohmresistors and maybe a few others. Resistors are color coded so that with some practice you can decipher resistance values from thecolor bands on the resistors you are using.


Capacitors also come in a wide range of values and are made using a variety of techniques. The capacitors that wewill use for signal conditioning are fairly small and have capacitances measured in Pico farads or microfarads. Somecapacitors are polarized and care must be taken to ensure that they are connected to a circuit with the proper orientation.

Trim Potentiometer Schematic

Trim potentiometers

A trim potentiometer is a variable resistor. It has three leads.

  • Positive power supply
  • Wiper
  • Reference power

The resistance of the trim pot is measured between the wiper and one of the other two leads. A trim-pot isdepicted schematically in Figure 1. An adjustment screw moves the wiper along the length of a coil resistor. The resistance betweenlead 1 and the wiper increases or decreases as the wiper moves further or closer.

The output voltage (Vout ) is related to the input voltages by the following relationship:

equation (1)

Operational amplifier (op-amp)

For this lab, we will use the LM741 op-amp. The LM741 is a very common op-amp package, with one op-amp perintegrated circuit (IC). (Many op-amp packages have two or four op-amps per IC.) A schematic representation of the LM 741 is shownin Figure 3. The semi-circular depression on the chip marks the top of the chip and the pins are numbered counterclockwise around thechip. The highest number pin is always opposite pin 1.

LM741 Pinout:

  • Null offset adjustment (not used)
  • Inverting (-) input
  • Non-inverting (+) input
  • Connect to -12 V
  • Null offset adjustment (not used)
  • Output
  • Connect to +12 V
  • Not used

Data sheets for this and other integrated circuits (IC's) can be obtained from the National Semiconductor website (www.national.com).

LM741 Connection Diagram

The prototyping board

You will build circuits for this lab using a solderless prototyping board known as a proto-board or breadboard.Breadboards allow us to connect circuits by plugging in components and wires. No soldering is required. A drawing of a breadboard isshown in Figure 4 below. As indicated by the gray lines, horizontal rows of connectors in areas B and C are internally connected. Whena chip is plugged into the board as shown, these strips give you four connections to each of the IC pins. The connections in regionsA and D are intended as power and ground buses. As indicated by the gray lines, the columns in these regions are tied togethervertically.

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Berger describes sociologists as concerned with
Mueller Reply
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Introduction to mechanical measurements. OpenStax CNX. Oct 18, 2006 Download for free at http://cnx.org/content/col10385/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Introduction to mechanical measurements' conversation and receive update notifications?