Analog System Lab Kit (STEM Product) - Review

Table of contents

RoadTest: Analog System Lab Kit (STEM Product)

Author: nixiefairy

Creation date:

Evaluation Type: Development Boards & Tools

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: I think it is a unique product for University Level Students. There are many kits available in the market relating to amateur electronics but finding a kit for university students is looking for a needle in a haystack. This kit fits the bill totally.

What were the biggest problems encountered?: More description was required in the manual. And support for simulations.

Detailed Review:

1. Introduction

       As a third year undergraduate student I have always tried to build the circuits taught in my college classes. The problem is, I find it difficult to find the components to build the circuits with. A university level student kit is what every college going electronics enthusiast needs. Texas Instruments has come out with the Analog System University Kit to help out in this problem. It is a kit containing all the basic components needed to implement the higher level circuits taught in college classes. Being a student, few circuits were a little difficult for me to implement, but with a little help I was able to implement the tough ones.

Here I would also like to take the opportunity to thank for selecting me to do the review on the ASLK and my college for allowing me to use the labs in after hours.

2. How I have gone about the review

I have organized this review as follows. It starts with the unboxing description followed by details of each of the individual experiments done according to the manual [http://download.mikroe.com/documents/specials/educational/aslk-pro/aslk-pro-manual-v103.pdf ].  My approach has been two pronged. I first simulated the circuits on a simulation software such as TINA / MultiSim and then made the physical circuits using the kit on the lab bench. I then compared the results of the simulated data with the real data. In the details of each of the experiment, I have published my results and findings.

2. Unboxing

The product was delivered in a week's time after I got selected for the road-test. The product was covered with brown paper and had arrived in a carton. I was impressed by the looks of the ASLK Pro Uni Kit and it certainly gets a 10/10 for its looks. The sliding well protected box of the ASLK Pro Kit consisted of the following:-

{gallery} Unboxing

The carton in which ASLK Kit arrived in

The kit itself!

First Impressions!

The Kit consists of the following

And the board itself!

Manual

Graph book

The schematics

 

3. Overview

The Board

     The board is a rock solid PCB and ideal for keeping in a Lab. The thoughtfully designed holes in the corners can keep the Board fixed in one place. It consists of rubber separation pads. I loved the way they have drawn the schematics on the PCB. It makes it easy for a user to make the connections.

 

{gallery} Board

Back view of the board

Powering up the board !

Side view

 

Manual

     The manual has a nice look and feel however, It does lack sufficient theory that is needed to go through some of the lab experiments. It is quite a piece of work to understand each of the experiments due to broken links in the online manual. The links in the manual consist of references of the lectures of the author, Dr. K.R.K. Rao. The lectures are theoretical and consist of a lot of derivations. However, they play very little role in helping out with the experiments. Practical performance and theory are two different aspects and should have been brought out clearly by the manual. I have mentioned for each of the experiments which links are broken and have suggested few of the links from which I understood the experiment from. Also few of the experiments give some unnecessary details that gave me no help in doing the experiments practically, other than summarizing the lectures given by Dr. K.R.K. Rao.

 

Graph and Schematics

There are a lot of unit, semi-logarithmic and logarithmic graphs. Schematics are well labeled.

 

Simulation

     I started out using TINA Basic Suite Edition. Being a MultiSim user for most of my earlier projects, I liked the interface of the TINA software. It had everything I needed (transfer characteristics, sweeps, transient analysis, analysis instruments and ,of course, the components). However, since I am more familiar with Multisimv14.0 and I had the demo version of TINA, I briefly touched TINAv11 in the first experiment only. Later, I simulated the circuits in Multisim14.0. Also, I have used FilterPro for designing the circuits of experiment 4 (more details in the experiment).

 

 

4. Experiments

 

Experiment 1

     Link given:  http://tinyurl.com/krkrao-nptel-lec7 and http://tinyurl.com/krkrao-nptel-lec8

     Link I suggest: https://www.youtube.com/watch?v=7FYHt5XviKc

    If you hardly know anything about OpAmps, then the above mentioned video is a great place to start. I started this experiment by first testing Unity Gain amplifier circuit on TINAv11. I was able to find the Pspice model of the TL082 with ease on the TINA database and it gave me the following output. I also built the same circuit on Multsim to check, if there is any difference. Again I was able to find the model with ease in the database. Finally, I checked the output on the scope.

 

{gallery} Unity Gain Amplifier

Implemented on Multisim

Output in Multisim : As one can see the peak is coming out to be a 997.68mV for an input of 996.72mV

Implemented on TINA

Output on TINA

Output on the scope: yellow is input and green is output.

Slew Rate: I was trying few of the problems given in the manual. One of them is this.

Gain-Bandwidth Product

 

As one can see the slew rate of the opamp TL082 is 10 V/us and the Gain Bandwidth Product is 3Mhz. Comparing with the datasheet which says the slew rate should be between 8-13V/us and Gain Bandwidth Product should be 3Mhz, it's perfect.

The next part of the experiment asks for a non-Inverting amplifier. So, I designed one with a gain of 5. Also, here I would like to mention that one has to shift the jumper of the DC-DC converter to external input (as suggested by , thanks), or they will be noise in both the input and output signal (I wonder why?), as shown below:

 

 

{gallery} Non-Inverting Amp

On Multisim

Multisim Output: For a 998mV input, I got a 4.99V

Implemented on TINA

Output on TINA: As one can see, for an input of 1V I got an output (dark green) of 5V.

Output on Oscilloscope: Green here is output.

 

After this part of the experiment, I noted that the output of TINA is very idealistic in comparison to Multisim.

The last part of the experiment is the Inverting amplifier:

I have used a 4k resistor as a feedback resistor, and 1k as Rin. Hence a gain of 4.

 

 

 

{gallery} Inverting Amplifier

Implemented in Multisim

Output on Multisim: 999.4mV input produces a -3.99V output

Implemented on TINA

Output on TINA

Circuit built on the kit

Output on the scope

The formulas(as well as the transfer functions) stated in the manual proved to be of no use to me for performing the experiments practically. Rest of the explanation of the opamp, the slew rate is pretty good.

 

Experiment 2

     Link given: https://www.youtube.com/watch?v=02cdB3Y2M0o&feature=PlayList&p=80DBC78FA0498727&index=8

     Link I suggest: https://www.youtube.com/watch?v=Ht48vv0rQYk

I was able to understand the Schmitt trigger well from the above mentioned link. The Schmitt Trigger is used for switching the output to Vsat accordingly when Vin reaches Vref. It is useful to produce a square wave for an input with noise.

 

{gallery} Schmitt Trigger

On Multisim

Output on Multisim

Output on the scope

As one can see, there is a difference between the outputs on the scope and Multisim( Vout=Vsat ,the board is clearly more accurate to this in comparison to Multisim). Now using the formula given in http://www.electronics-tutorials.ws/opamp/op-amp-multivibrator.html :



Here beta=r1/r1+r2. So, 1/1+10=1/11. Hence, Vref=Vsat/11 that is 0.91V. Though somewhat visible, one can see that somewhere approx. 0.91V the output shifts from positive to negative rail.

Now for the Astable Multivibrator:

{gallery} Astable Multivibrator

Implemented on Multism

Output on Multism: Peak Voltage across the cap is 764mV

Output on Multism: Output of the astable Multivibrator is +-8.64V

Output on the scope

Here we see that there is hardly any difference in the values of Vsat in Multisim and ASLK Pro. Also by the formula:

{gallery} Astable Formuals


Here beta= r1/r1+r2= 1/11, R= 4k and C=1uF

So T= 2 * 4k * 1u *ln [(1 + (1/11))/(1 - (1/11)] = 1.458ms

So it kind of matches with the scope results and Multisim too.

 

Experiment 3:

    Link given: none

    Link I suggest: http://www.electronics-tutorials.ws/opamp/opamp_7.html and http://www.electronics-tutorials.ws/opamp/opamp_6.html

One can use the opamp to perform the mathematical functions differentiation and integration. For the differentiator:

 

I used the circuit given in the manual. But I was getting a lot of noise. So I used the circuits mentioned in the links given above, i.e used capacitor in parallel to the resistor R. This attenuates the signal at high frequency and hence removes the unwanted spike I get when I am changing from positive to negative and vice-versa.

 

{gallery} Differentiator

On Multisim

Output on Multisim

Output on the scope: This without the capacitor attached parallel to R.

Output no the scope: Kind of matches with the simulator

Photo of the connections

The next part of the experiment is to implement an intergrator with the TL082.

Again I have used a resistor in parallel to capacitor C. Also,

Av=(-4/1) * 1/(1+ 2 * pi * 1k * 0.1u * 4k)= - 1.14

So, onto the results!

{gallery} Integrator

On Multisim

Output on Mutlisim

Output on the bench

Another output on the scope: Square wave

Output on Multisim : Square wave

Output on the scope: This is without adding the additional resistance to the integrator. I had to provide a Voltage offset of -7.1V to bring it to the 0V axis.

     The results of the simulation and the kit matched perfectly. However being a practical manual, there should have been a mention of adding a resistor to the integrator and a capacitor to the standard differentiator circuit.

Experiment 4

Link given: http://tinyurl.com/krkraonptel-lec12  < broken >

Link I suggest: http://www.electronics-tutorials.ws/filter/filter_5.html and Introduction to Filters

 

This experiment asks the reader for designing a LPF, a HPF, a BandpassPF and BandstopPF. I have used FilterPro to design the three filters (Low, High and Band-pass).

It's a pretty neat software; it starts with a wizard asking which kind of filter you want and asks you the specs of what kind of filter you want ( Gain, allowable ripples, different limits to the frequencies and the passband frequencies). It then asks for which second order frequency response you want. Finally, it asks for a filter topology. For experimenting, I have kept the topology set to Sallen-Key for all three filters and the response as Bessel.

However, the only problem with the software is that it considers an ideal opamp. We can't chose the opamp we wish to build the filter with. Other than that, I was very pleased with the interface of the software and is a great tool for designing filters.

 

Low Pass Filter:

Results of FilterPro : https://drive.google.com/file/d/1U6J5IitfnzOpDNuDKIzqicVv9V-tV3MF/view?usp=sharing

I had changed the values of the LPF on the simulation to get it to match the values of resistors and capacitors on the ASLK. And it worked perfectly. I then simulated it on Multisim and the bench.

But firstly, we will use these formulas to find the cut-off frequency and gain

fc= 1 / 2 * pi * sqrt ( 66k * 10k * 10n * 2n) and Av= 1 + ( 4 / 1)

fc = 1185.3 Hz and Av=5V/V

Now let's see the simulation:

{gallery} LPF

On Multisim

AC sweep: At -3b it is approx. 920Hz.

 

And on the bench:

 

Hence, it works perfectly

Bandpass Filter:

     FilterPro Result: https://drive.google.com/file/d/19Gm5Lw6Q-J22gDOSrY2G3YYvgfaOJtgZ/view?usp=sharing

Here, I have used the circuit as suggested by Filterpro. I made the circuit on the breadboard to check if it works correctly or not. Firstly numerically we will verify:

Now modifying and using the above mentioned formula, we get:

fr = 1 / 2 * pi * sqrt( C1 * C2 * R3 * (R1||R2))

fr = 1 / 2 * pi * sqrt( 100n * 100n * 470 * ( 4k || 390 ))      <See circuit below>

fr = 3894.4 Hz

Onto the simulation!

 

{gallery} Bandpass filter

On Multisim

AC sweep: As one can see, fr = sqrt ( 2.6k * 5.82k ) = 3.9kHz

 

Here is the scope result:

 

 

High Pass Filter

FilterPro results: https://drive.google.com/open?id=1g-0_D0EeCyMe0fj4FmmCkDIUxMjXkyYS

I have just added the results of FilterPro and the circuit implemented on Multisim for this filter, for those interested:

Experiment 5:

 

Link given:  http://tinyurl.com/krkrao-nptel-ic-lec23

Link I suggest: none

For simulating on any of the two software, I was unable to find the spice macro model of the MPY634.  I was ,however, able to dig up this link https://e2e.ti.com/blogs_/b/designproject/archive/2013/08/07/adventures-in-analog-part-2-eliminating-the-power-supply-no… . If one goes through the site, one will find the circuit on self-tuned filter from which I made the circuit on the kit.

 

Self-Tuned-Filter

 

I am not so sure that the waveform is correct for an input of sine wave:

 

 

Experiment 6

The Voltage Controlled Oscillator is an electronic oscillator whose oscillation is controlled by the input voltage. Now to calculate the frequency of the oscillation, I have used the formula on the manual:

However, here Vc is the input voltage, but, what is Vr? There is no reference to Vr in the manual. Also the internet has no formulas for a VCO. So I planned to use the other formula suggested by the manual for a free running VCO without any input:

So, f = ( 1 / 4 * 1k * 0.1u)(10k / 1k) = 25kHz whereas by scope and simulation it is 16kHz.

For the Vco, I designed the circuit on Multisim and implemented it on the kit later. I used the preinstalled macro model of an analog multiplier available on Multisim.

 

{gallery} Vco

On Multisim

Output on Multisim

Vco without the analog multiplier : Blue - Integrator, Yellow - Input and Green - Schmitt trigger

Circuit

 

I have added the video for the VCO with the MPY634 and as I am changing the input to it using a trimmer:

 

 

 

Experiment 7

Link I suggest: https://www.youtube.com/watch?v=0jzLDe950AY

The above link is great link to understand PLL.

For the Multisim model I used:

The output of the Multisim model looks quite incorrect. I am assuming, due to the wrongly added multipliers, the output is wrong.

However, I am quite sure that the output on the PLL on the scope is correct. When there is a slight change in the output there is a change in the phase as shown by the blue waveform (channel 3).

 

 

Experiments 11 and 12

These two experiments I have performed with the sole purpose to check whether the TPS40200 works correctly or not. Plus, again I couldn't find the PSpice macro model of TPS40200.

Firstly, the LDO should give me a constant output of (Each division in the video is 5V/unit. Sorry for cutting off the cursor display )

 

Secondly the DC/DC converter should give me

 

 

Once again, yellow is the input and blue is the output. Here, I would like to mention that there is a noise in the output signal when the input increases beyond 8V ( One can see the ripples there). When I checked the output across TP5 and TP7, the output is a constant 5.2V. In the scope the green line represents the 'output across these tow terminals and one can see no ripple. It may be probable that C11, C12 and R3 are causing some disturbance, but I don't think that's possible.

 

 

Conclusion:

This review was a great learning experience for me. Once again, I would like to thank for selecting me for the review . The ASLK Pro in the end, met my expectations but the Manual needs work and was below par. When I enrolled for this roadtest, I was under the impression the manual looked great and well made and it explained everything, and I would not face any problems while I am going through it. Sadly that was not the case. The manual starts off with a great start along with well explained experiments. But from experiment 4 the theoretical content in the Manual starts dropping . Also there is a lack of the Pspice models for most of the ICs in the ASLK, making it all the more tougher to simulate the experiments on a simulation software. I think TI should  provide the PSpice macro models for ease of access.

To summarize what I have said: For a 149$ , the ASLK is a kit which does show promise if it works in the following avenues:-

  • PSpice models for each of the ICs is a must.
  • A review of the manual is a must with addition of relevant theory in the experiments as indicated.

 

Other than, that the board itself was great and the whole experience was fun! I suggest this kit for someone who is already familiar with the theory of all the experiments in the ASLK Pro.

I wish to end this review with a poll:-

Anonymous
  • I am glad you like the review, Gene! It is really frustrating to see a product with huge potential lagging behind because of the manual. I hope TI updates it!

  • Eashan,

     

    Great review and write-up! It seems like you put a lot of the circuits to work. I also like the you were a little tougher than most people on your scoring, it only helps the sponsors if you fairly show some ideas where you feel that they could improve their product.  Well done!

  • Great detailed review, I can see a lot of effort has gone into it.

     

    Kind regards

  • Thanks shabaz,

    I ran a search through both the TINA's and Multisim's database and couldn't find any of the models. I also checked ,the component's sites. They don't have the models. But the manual, does have the schematics made in TINA. I mean, the looks of most of the components do match. Probably TI has forgot to upload them ?

    Didn't know more comprehensive softwares are required for multipliers. Will definitely look this up. Thanks!

  • Thanks for the feedback, Gerrit! Strangely enough, when I checked the output across the terminal TP5-7, I was getting a clear output. I think, the capacitors C11 and C12 have defeated their purpose...

  • I am glad you like the review, John !

  • It does look like an awesome kit. Did you check TINA, in case that could simulate the parts you need? There are extremely good simulations of the power supply parts (the TPS40200 that you mention) directly on TI's website, but there is also likely to be support in TINA. Regarding the model for the multiplier, sometimes that is not available because not everything can be simulated practically in SPICE (that multiplier may have behaviour that is inaccurate to model without a very detailed simulation at different frequencies), and so for maximum benefit of an accurate model sometimes different software needs to be used to simulate it - for example RF mixers have their own simulation tools (e.g. Agilent/Keysight ADS). In such simulators they end up using tables of information to more precisely model parts at specific frequencies, and also some very iterative (sometimes slow, but accurate) techniques for calculating outputs, which don't lend themselves to a real-time output you can connect to a virtual oscilloscope as with some SPICE based simulators.

    Excellent report by the way, it certainly helps people decide if this product suits them!

  • Hi Eashan,

     

    nice review, it confirms my own findings.

    Regarding the noise from the DC-DC converter, this is most likely generated by the switching circuit which operates on a high frequency and picked up by all the wires in your experiment.

  • Hi Eashan,

    Thanks for the great road test report. I enjoyed learning more about this product. I didn't even realize they had 100 in 1 project kits for adults. Pretty cool. I had a little trouble with your scrolling pictures until I learned that by clicking on one of the arrows I was able to take control of the scan rate. I look forward to seeing your future posts and projects.

     

    John