How Does the 3-20V MOSFET PWM Trigger Switch Driver Board Work for Beginners?

... as featured in Julian Edgar's excellent Electronic Building Blocks two pages in the current (May 2019) issue of Practical Electronics magazine - 3-20V MOSFET MOS Transistor Trigger Switch Driver Board PWM Control Module
This is not so much a question, more a request.

Dear Mr. E:

* for those of us who are not electronics experts
* who don't earn our daily bread employed in electronics
* and who haven't been "doing it" for years, accumulating vast amounts of expertise on the way

*BUT all the same are mighty interested in the subject ...

... can you please make sure to keep it simple, really simple, so that even "mere" hobbyists like me can understand.

So far, you've been doing great, ie. "great" from my  point of view and I'd imagine that of other hobbyist readers.

A lot of the rest of the stuff in the new-look Practical Electronics mag is getting to be highly technical, which must suit the very knowledgeable just fine and dandy (stops 'em getting bored).

What would be really really nice, Mr. E, would be come next month , or soon-ish at least (when I get my hands on the frequency generator module that you also feature in the May issue of the mag) is some simple, easy-to-understand diagrams showing how you wire the frequency generator module and the MOSFET PWM module all together.

That would be lovely and ta' awfully if you can do this.

Michelle

PS. I now what PWM means. It means pulse width modulation. You see, I'm coming along.

Hi Michelle,I am over 70 years old and the problem has not changed in all of 60 years.I started electronics when I was about 10 years old when thermionic valves were in their prime, all the books and magazines at that time considered that I new all the basics. No internet then so learning came from failure and never having enough pocket money. I have since learned from experience (from working in medical science, electronics, mechanical engineering and civil engineering, that experts come in different packages.The true expert can teach at all levels of knowledge, one I new and respected greatly, said for now consider the answer you need right now is that what we do in this technology is magic and then made me his student and taught me the spells needed to understand that magic.Most experts know what they talk about but have forgotten how to explain the fundamentals that they built their knowledge from.Some Experts know all the big words and can put on a great show but do not fully understand the basic principles the technology they talk about is based on.Keep asking why why why.Good luck to you in your learning.

Although our projects are published by arrangement with Silicon Chip we do have plenty of home grown material including our Teach-In series which is designed for the benefit of newcomers.The Building Blocks series is intended to show applications of cheap 'n cheerful off the shelf modules and the writer doesn't have much room (two pages) to play with, so rather than going into electronics fundamentals themselves (like eg Circuit Surgery or Teach-In do) a certain amount of prior knowledge is assumed for this series. However there's never usually anything wrong that an email to us or a post into this forum won't cure, so feel free to ask away!-- Alan W / PE

Michelle: I just turned 70, and I started electronics when I was in the 4th grade of elementary school, devouring the 1958 "Radio Amateur's Handbook", building crystal radios and then radios using vacuum tubes. As Conrad writes, "Keep asking why why why."
I suggest you look at Max Maxfield's column "The Best Way to Begin Learning Analog Electronics" here on EEWeb, where Max, myself, and others are suggesting reading matter to learn from, starting from the very beginning. The resources noted there make it clear that there is more than one way to think about it, and thus more than one way to do it.
J. K. Rowling's Hogwarts is an engineering school, where students learn to master technologies (what Rowling calls magic). Arthur C. Clarke quote: "A sufficiently advanced technology is indistinguishable from magic."Pulse-width modulation PWM is a method of digital-to-analog conversion where a signal switches rapidly between two values. The switching pattern is chosen to average over time to a desired slow analog signal waveform.

Hi Michelle, good to hear from you again. I certainly try to aim the EBB column at people who, perhaps a bit like me, are not 'real' electronic experts but enjoy playing with electronics - and especially in achieving an immediately usable outcome. You're right - I should have included a circuit diagram showing the connections. Here is the circuit: 
In brief: - 12V nominal power supply fed to both the MOSFET module and Frequency Generator module - PWM and Ground connections from Frequency Generator module to MOSFET module, as labelled on the modules- Load connected across Out (+) and Out (-)And here is the actual wired circuit, controlling the speed of a small electric motor:

Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you
- St. Matthew, Chapter 7 Verse 7
Thank you so much, Julian. Your circuit diagram and photograph are exactly what I was seeking. The electronics "experts" among the Practical Electronics readership probably find this kind of basic level help superfluous and maybe perhaps even an annoying waste of magazine space . But it's precisely these  sort of  what-goes-where, what-connects-with-what diagrams/pictures you have provided here that amateurs like me find so valuable. 
Michelle

These basic-level, what-goes-where, what-connects-with-what diagrams/pictures are essential. Michelle, keep building, keep asking questions, and let us know how your project works out. What are you using your PWM for? I've always been an amateur, even when I was a professional, and I'm still an amateur now, still learning by doing.Thanks for the St. Matthew quote.

"What are you using your PWM for?"Principally for driving motors, Peter, but also simply for the interest of getting Julian's circuit up and running and seeing it work. Thank you for your encouragement, everyone.
Michelle

Hi Michelle, as I wrote in the article, the  Frequency Generator module / MOSFET module combination are excellent in teaching what PWM means in terms of power control. Start just with an LED (with resistor for 12V operation) connected across the Frequency Generator module output, with duty cycle set to 50 per cent. Start at say 1Hz frequency  and watch the LED flash on and off, half the time on, and half the time off, once per second. Change the frequency and watch the flash rate change. Then do the same, keeping a constant, slow frequency and changing only the duty cycle. Then add the MOSFET module and connect  a small electric motor, like I have done. Experiment with what frequency allows smoothest control of speed of the motor when you alter duty cycle. In the pic above I was using about 130Hz. (The best frequency will depend on the motor you're using.) It's a lot of fun being able to slow the motor to just a crawl, and then wind it up in speed. You can also think of it like this: at 50 per cent duty cycle, the motor will act very much like it is seeing 50 per cent of the supply voltage - after all, that's the average voltage it is seeing. If you have a small 12V filament lamp (eg car interior lamp), try that with the above set up. Again vary the drive frequency and duty cycle. See how, because of the slow reaction time of the filament compared with the LED, it behaves slightly differently eg you won't be able to flash a filament lamp fast. All lots of fun, and in the area I write most about (car electronics), PWM power control has a host of real-world applications. 

The Building Blocks series is intended to show applications of cheap 'n cheerful off the shelf modules and the writer doesn't have much room (two pages) to play with, so rather than going into electronics fundamentals themselves (like eg Circuit Surgery or Teach-In do) a certain amount of prior knowledge is assumed for this series. However there's never usually anything wrong that an email to us or a post into this forum won't cure, so feel free to ask away! dqfanfeedback