Analog Discoverymy adventures with
- Oscilloscopes can display fascinating voltage vs time pictures and also the phase relationship between two voltages :-))
- In the Army, 1955, I bought and constructed a Heathkit 'scope that was advanced enough to display the TV color-burst frequency of 3.579545 MHz :-)) - probably a o-9 model - the ad said the color burst display was only 3 db down. specifications, schematic.
- The above disappeared in the intervening years - but I grew lonesome for another scope, but by then Heathkit had disappeared and e-bay not yet invented.
- Then I occasionally bought a 'scope from flea markets - but the bulk of the needed accessories such as signal generators, power supplies, drawers of components just didn't fit a family situation :-))
- While at Measurex I would occasionally borrow a company 'scope to help with a project, such as adding added (dynamic ;-)) memory to the family PET computer.
- Much later I started looking at "USB oscilloscope" which are controlled and displayed by a PC - but they seemed limited -
- Jan 2013 I noticed the "Analog Discovery" unit by Digilent which combines
oscilloscope, signal generator, digital I/O, and +- 5 volt power :-))
- I down loaded their Analog Discovery software package with reasonable user interface. The demo mode seem flexible and well worked out -
So I ordered the Analog Discovery kit along with their "Analog Parts Kit" without examining possible competitive offerings from others.
Table of Contents
- In the package
- Some fun with the 'scope
- Parallel Resonance
- Trying the Microphone
- Handy Component Codes
The surprisingly small package arrives :-))
What do we have here??
One greeting card sized cardboard saying buy AnalogDiscovery and giving the URL to the web site.
There are five YouTube videos for training, [ see Training below ] so the lack of a big heavy manual is not a hindrance - a person would really not use it, much preferring to use the convenient on-line material instead !!
A neat little storage box with device and USB cable. I plugged it into my PC - the software recognized the device immediately, and the device signal generator sent the commanded tones to my now plugged-in ear phones - GREAT, no muss, no fuss :-))
Loopback is accomplished with supplied male-male connectors, and using the instructions in here was able to view the signal generator output with the oscilloscope :-)) - GREAT, no muss, no fuss :-))
Looks nice and neat, such tiny components, a number of DIP packages, but the rest is very much smaller since the 1970s, see below. I feel very out of date.
How to connect probes to them to the AnalogDiscovery is on the web site link above -
I put Training here because with out that on-line aid - I was helpless -
There are five Analog Discovery training video series on YouTube, starting here.
Currently, YouTube gives a thumb-nail of the next in the series in the upper right hand corner of your monitor. Clicking there will start the next in the series :-))
The very good instructor assumes that you have the "Analog Parts Kit", or an extensive electronics warehouse. I feel very lucky to have purchased the "Analog Parts Kit" with the order.
The first project in the training is to wire up (on the little plugboard) a blinking LED in series with a resistor - (really needed or you smoke the LED, which is extremely voltage sensitive.)
I quickly learned that there is over-current detection in the AnalogDiscovery which shuts down all outputs and gives a warning box on the monitor. Gads - my bad wiring, try again. Gads, now what ?? After some fumbling about I find that I have set a +5 volt offset into the Signal Generator, and that 5 volts plus the AC output I set caused this over-current situation - removed the +5 volt offset, and every thing worked as suggested in the video.
There are five YouTube videos for AnalogDiscovery:
- Getting Started - Quickstart #1 - https://www.youtube.com/watch?v=aYgFKIsrOYQ
- Voltage Tool - Quickstart #2 - https://www.youtube.com/watch?v=Gdl7hPFaPWI
- Voltmeter - Quickstart #3 - https://www.youtube.com/watch?v=Va1lURqbmew
- Arbitrary Waveform Generator - Quickstart #4 - https://www.youtube.com/watch?v=rXJXphcV1Vk
The Arbitrary Waveform Generator has many functions, this is a good start -
- Oscilloscope - Quickstart #5: - https://www.youtube.com/watch?v=pmJzBCv5G2g
Any flexible oscilloscope, and this is indeed!! is almost a study in itself !!
- Many new concepts and functions !! - This is just a good working start !!
- A full treatment with exercises would be several days of serious study
Please note: after an initial introduction to complex equipment such as the signal generator and the 'scope above - most folks go into a period of trying out different options which might be useful in different circumstances - Not advertized nor discussed in the videos, but interesting to me were:
Both of which are also available in the package :-))
- X vs Y plotting for signal phase relationships
- FFT ( Fast Fourier Transform) computing and display
Both were fairly intuitive, try 'em out and see what happens, learn by doing - that seems the modern way for our very complex world -
Here is the little LED and resistor circuit built up and used in the above lessons. And this is the dual trace oscilloscope view of the proceedings.
- blue trace - voltage across the LED
- orange trace - current through LED
I found identifying components "interesting"
The good news:
- Very compact and modern
- does not take up much room :-))
- "Analog Parts Kit" has this array - also available locally. (you may have to click on the image to enlarge it)
- A little sheet of component codes would be nice.
I didn't remember the 3 digit capacitor codes, 104 is 0.1 ufd, 102 is 0.001 ufd, is useful
- A good magnifying lens is likely necessary for most people
The bad news:
- Very compact and modern
- you need good eyes and steady hands :-((
Connectors Resistors, I'm used to the size of the two on the left from my junk box. How good are your eyes seeing the color bands on the right resistor? The picture on your monitor is likely 2.5 times actual size. Big hands, tiny components -
- The labels are as small as the components
- The labels on the DIP packages are grey on black
Enhanced in brightness & contrast -
The following comments are from Doug Mercer of Analog Devices responding to my question contrast -
"You are very correct in pointing out the low contrast of the laser branding. This is not unique to ADI, most high volume IC manufacturers use laser branding. I've found that oblique lighting tends to enhance the contract of the branding."
- The Surface Mounted chips, on "DIP Adaptors".
Enhanced in brightness & contrast.
- This Digilent document gives the name of the chip and a link to Analog Devices documentation
- The following comments are from Doug Mercer of Analog Devices responding to my question about pin matching -
... "there is a number "1" printed next to the adapter pin 1. They are always in the lower left corner with the "1" right way up. Also the solder pad for that pin is square not round like all the others. This is per the standard DIP package convention. How the IC pins map to the adapter pins is always one-to-one. So when reading the ADI datasheet pin 1 on the IC package is pin 1 on the adapter etc. No need to trace the wires."
Some fun with the 'scope
We have electric tooth brushes in our house - supposed to be very good.
A question - the base is plugged in, and the battery/motor/brush assembly sits on the base to charge the battery - but there is no exposed copper conductor visible to conduct the electric energy.
How does the energy get from the base to the battery???
Here is an electric toothbrush with its charging base. Here is the charging base, no contacts, with an inductor as a sensor, connected to the Digilent "Oscilloscope".
Here is the Digilent "Oscilloscope" as seen on my monitor :-))
- We have set up a single scan, the vertical gain and horizontal timing is plain to see.
- We have also set up a horizontal measurement, lower right, selecting "Frequency"
- Note the frequency 92.657 kHz, and the method -
How is that for cute and handy ;-))
The base continuously oscillates at about 100 kHz, and when the toothbrush sits on it, that energy couples into a coil of the toothbrush and charges the battery :-))
Learning electronics, after DC theory and circuits, not very dynamic, hopefully -
usually AC theory and circuits is taught, life gets "interesting" !!
Skipping series RC and RL circuits as lessons in phase shifting,
we come to parallel resonant circuits, and life gets more interesting :-))
So, here we are all connected up with AC source across everything and voltage sensing across the parallel circuit and across the resistor :-))
And the wave forms :-))
Orange is voltage across the resonant circuit, Blue is voltage across the resistor
Note the different phase shifts :-))
A little off resonance, 40.35 kHz Just about on resonance, 48.5 kHz Buildup of oscillations with start of excitation Showing XY at about resonance, 48.5 kHz FFT w Hamming window w constant excitation Using triangle wave for excitation, note that there is very little harmonic power across the resonant circuit - the orange line -
Trying the Microphone
Lets try the enclosed microphone, IC10 - ADMP504, and show the wife some natural wave forms :-))
The Analog Parts Kit links to the data sheet which says that it required 3.3 volts power - our ANALOG DISCOVERY regular power is +- 5 volts. We have a choice:
- a) use IC8 for 3.3 volts
- b) use the Signal Generator to provide the 3.3 volts
Choosing simplicity, lets use the Signal Generator, and watch its voltage for sag.
Now to the microphone, I printed out the linked Data Sheet for the ADMP504
I turn the carrier over, I can see an alignment dot - OK - an ink mark - no, I don't think so - I bet it is the other end - The pictured configuration works :-))
So, lets wire it up and set it up
The 3.3 volts from the Signal Generator is applied to power the IC-10
Well, the output has a bias of about +0.8 volts and little amplitude -
- So I put a small capacitor between the output stage and the oscilloscope
- Set gain to 5 mVolts/vertical division,
say "AH" into the microphone for the doctor, and look at that :-))
Handy Component Codes
Posted by: "Jim Sanders" anfps26
0 1 2 3 4 5 6 7 8 9 . . . Bad Boys Rape Our Young Girls But Violet Goes Willingly Get Some Now.
Resistor Color Code - from http://itll.colorado.edu/images/uploads/resistorchart.jpg
That's all for now folks -
Updated through February 21, 2013