Science and Engineering Learning Lab

A challenge was presented to me requesting I develop an inexpensive electronics learning lab that would

a) engage the student
b) present concepts clearly and concisely
c) be simple to learn and use
d) be hands-on
e) be inexpensive

The initial target audience are my grandchildren. However others may find this interesting and possibly useful.

System component selection
Primary considerations for measurement devices were simple operation, highly visible large display, inexpensive. Accuracy and features were not a priority.

Primary considerations for science kits were ease of experiment construction, highly visual documentation with explanations at appropriate level for the student.

The Radiotron handbook is included as an inexpensive resource for further information when the student advances beyond the initial lessons. Active circuit elements in the handbook are vacuum tubes rather than transistors. Circuit theory is largely the same independent of active devices. This particular book contains much of the information presented in the first years of University level Electrical Engineering in a concise format.

After reviewing numerous science kits and inexpensive measurement devices the following emerged as the top contenders:

1) oscilloscope as the primary measurement device
a) FNIRSI 1014D ($175 US)
https://www.amazon.com/FNIRSI-1014D-Dual-Channel-Oscilloscope-Generator-Bandwidth/dp/B097T5NRTZ
This one has a signal generator limited to a single amplitude

b) PicoScope 2204A ($165 US)
https://www.amazon.com/Pico-PicoScope-2204A/dp/B00GZMRZ3M
The PicoScope signal generator has adjustable amplitude which increases its versatility

2) Snap Circuits SC-300 ($50 US)
https://www.amazon.com/Snap-Circuits-SC-300-Electronics-Exploration/dp/B0000683A4

3) RCA Radiotron Designers Handbook (used)
price varies, often under $20 US depending on which edition
https://www.amazon.com/Radiotron-Designers-Langford-Editor-Smith/dp/B000XTUPD0

DMM vs Oscilloscope
While a DMM can provide considerable insights into circuit behavior an oscilloscope adds the dimension of time which increases the visualization impact. This particular DMM was considered, and if budget permits makes a great addition to the learning lab:

Labloot LB1041
https://www.amazon.com/dp/B0BG563XMK

These are not Tektronix, Keysight, Fluke or Picotech instruments. Accuracy, features, etc. are much lower than usual lab grade devices. However they are inexpensive, with large displays and due to limited features, quite well suited for a learning lab. Picotech is listed, as it has accuracy and features that will continue to serve the student well later on, but requires a computer or laptop and investment of time learning a necessarily more complex interface due to the tremendous level of features available.

Two learning lab experiments are shown below.

Class A amplifier




A basic voltage amplifier with input and output displayed.
The student can make adjustments and observe results immediately.
This one is particularly useful in exploring Class A audio amplifier behavior.

Relaxation oscillator




Opportunity to observe capacitor exponential charging behavior in action

This Learning Lab system was approximately $250 US, just a little over the average cost of a college textbook in today’s economy. My grandkids are able to construct the circuits, operate the measurement devices and observe changes they make to circuit parameters. They are learning about linear and exponential equations and how mathematics connects directly to circuit design. They don’t get bogged down with complex computer interfaces and can make some extrapolations from their lessons to real world behaviors. Future possibilities are limited only by their imaginations, which keep expanding all the time.

 

Looks like a blast! Any particular safety precautions? Age of students?

 

Snap Circuits utilizes 2 to 4 AA batteries depending on the circuit. In these pictures I am using the battery eliminator which is a wall wart power supply having 3, 5 and 6V outputs. Even the oscilloscope is running off a USB power module. Everything is 6V and below.

Age of students is very much dependent on the academic and emotional level of the student. Fine motor skills are not a requirement though they help when adjusting the oscilloscope. Snap Circuits recommends age 8 and up. I am finding reviewing my own life lessons still very much a lot of fun with these modest components.

 

My two kids are 5 and 7. The older one was hooked to the scope since she was 3 yo.
The younger simply loves the different electronics components as toys.

I've been too crude to make things nice to them - your setup is inspiring.

The measurement devices you listed are not toys! These appear as great budget finds for hobby people.

 

This one is for bigger kids, but plenty accessible - https://www.falstad.com/circuit/circuitjs.html

I like recreating known circuits on it to see what makes them tick.

 

Using the Science and Engineering Learning Lab to learn about class A amplifier bias adjustment for minimum observed harmonic distortion and calculate amplifier gain.


Class A amplifier bias adjustment goal is to minimize observed harmonic distortion and keep the output signal in the most linear region of the amplifier active element, in this case a BJT, the red triangular component on the right side of the circuit layout.



In the oscilloscope screen shot above bias has been adjusted such that amplifier output is saturating (clipping) the positive power supply limit as seen by the flattening of the time domain (blue) trace and the 2nd and 3rd harmonics in the FFT (red) trace.



As the bias slider is adjusted up and down observe the amplifier time domain output go from positive supply saturation to negative supply saturation. The FFT harmonics are reduced in amplitude as the amp output nears the most linear point of operation. When the harmonics disappear amplifier output is at the most linear operating point.



Optimum bias where this class A amplifier operates in the most linear region.



Amplifier gain is calculated by dividing output level by input level. In this example:
Output = 3.87 Vpp
Input = 0.211 Vpp
3.87 / 0.211 = 18.34
A = 18.34
converting to dB A = 20*Log10(18.34)
A = 25.27 dB
This amplifier with this specific BJT has a fixed gain of 25.27 dB

 

@Amir, ASR - are you seeing this?!

 

Extremely interesting!
I came up with a similar project (in truth, it's closer to the "Snap circuit" you mentioned), which I built 6 months ago, also to ignite love for electricity and physics to kids.
More "physics"-oriented than "electronics", I would say.
You can see some pictures and videos here:
https://photos.app.goo.gl/2g3uQjyJ65p52mg68

Thank you for the details and link @atomicbob , this might be very useful

The idea is to improvise and plug some small independent modules in either serial/parallel connections.
Those modules are of many different types to provide some "guts feeling" on the various physical phenomenons behind (light bulbs, motors, vibrators, speakers, leds, fans, capacitors for storage etc...), so I had the additional constraint to make the circuit/components safe to use in any parallel / serial configuration.

The board includes a global switch on the top left and offers simple arrangements (from left column) to gradually more complex ones (right side, 2, then 3 serial).
It's a LOT of fun, not only for kids.
You can:
- Connect 1 light bulb alone and see it being very bright compared to 2 or 3 light bulbs in serial.
- Put a light bulb and a motor in serial, and see the light bulb shine much stronger when you block the motor with your fingers. (back EMF)
- Put two motors in serial and see one go much faster when you block the other one.
- Listen to the electrical noise the fan/motor make on the power supply line, add the capacitor in parallel to kill the noise.
- See the effect of capacitor charge/discharge on light bulb/led/motors, and see that energy is dissipated at different speed.

All the while, battery voltage and current can be monitored on the top left, which gives an idea on what's happening.

I have many more ideas on modules I could build, and just need to execute now before my friend opens her school (like a coil and iron dust to visualize magnetic field, magnetic pendulum / levitation, electrical arcs from interrupting coil current...

Any constructive feedback or ideas to make this more intuitive / playful / accessible for kids is welcome.

 

I taught both my boys using the exact same snap circuits setup. And with DMM. Alas, they had but only a passing interest. But one did turn out an airline pilot, and the other a mechanical engineer…. So, maybe it helped?

Epic

 

Everyone talking about their kids and grandkids and me thinking how good this would be for me.

 

While my initial target audience is my grandchildren, I am willing to entertain zoom sessions to help anyone wishing to learn more using this learning system. Wish I had this when I began my journey into electronics. I did have an AC Gilbert Erec-Tronic 11053 but not the advanced oscilloscope, nor even a VOM.

 

My first lesson in circuits involved a variac, a breadboard, and "accidentally" embedding chips into the ceiling...

 

Some additional example resources to expand on the concept:

Arduino experiments
https://www.amazon.com/ELEGOO-Project-Tutorial-Controller-Projects/dp/B01D8KOZF4

Alligator clip leads for interconnection between Snap Circuits and Arduino
https://www.amazon.com/gp/product/B06XX25HFX

Two example books for self directed learning
https://www.amazon.com/Understanding-Basic-Electronics-Softcover-ARRL/dp/0872590828
https://www.amazon.com/Electronics-Beginners-Introduction-Schematics-Microcontrollers/dp/1484259785

How to use an oscilloscope
https://www.amazon.com/HOW-USE-OSCILLOSCOPE-Comprehensive-oscilloscope/dp/B0CWVM67TT

And an absolutely ridiculously inexpensive handheld oscilloscope:
https://www.amazon.com/gp/product/B0C6XPVLPZ

Granted, it has very limited bandwidth, but for low frequency experimentation it still is a useful visualizer.

 

And a simple oscilloscope you can build to see how they work!

https://www.jameco.com/z/WSEDU08-Velleman-Whadda-Educational-LCD-Oscilloscope-Kit_2261959.html