Q&A with Forrest Mims III: Author

Forrest M. Mims III has written over sixty books about science, computers and electronic circuits that he has tested and built. We were able to wrack his brain and learn a little more about the man who has sold over 7.5 million copies of his books. Throughout the Q&A we were able to learn a little more about how he got his start, his favorite build and how he is able to turn circuit analysis into something that DIYers are able to understand!

The Shack Blog: How did you get your start in electronics?

Forrest M. Mims III: My father built a crystal radio for my brother and me when I was 11 years old. That radio project got me started. My first “circuit” was a headlight for a soapbox racer made from a flashlight bulb soldered into a hole in the bottom of a tin can. The switch was a nail that rotated over a second nail. Unfortunately, the switch was connected across the battery and not in series with the battery and lamp. That meant the battery was shorted when the light was off. After the first battery was quickly discharged, I learned how to troubleshoot a circuit and quickly found the silly error.

TSB: You’ve built a ton of cool projects over the years – which one was your favorite, and why?

Mims: I built and published a series of solid state oscilloscopes using arrays of LEDs. While their resolution was low, they worked. I also designed and built from discrete chips a 4-bit digital processor that could be programmed with several instructions. My favorite projects were the lab kits I designed for RadioShack, especially the Electronics Learning Lab and the RadioShack Sun & Sky Monitoring Station. I just returned from 13 days at Hawaii’s Mauna Loa Observatory, where I calibrated the first Sun & Sky Station for the ninth year. I use this device every day the sun shines, and it provides beautiful data.

TSB: Were there any circuits you designed but eventually excluded from the books because you felt they were too complex?

Mims: I published only the block diagram and instruction codes for the full processor circuit described above. I didn’t publish full details for various travel aids for the blind, rocket instruments a thumb-size Geiger counter and a host of other projects..

TSB: How do you go about translating something like circuit analysis into an understandable application for the DIYer?

Mims: Easy. Since my degree is in government, not electronics, I explain circuits only after I build and understand them. If I can understand them, then so can the readers. You might be surprised by several letters I’ve received from PhDs and others who claimed one of my circuits would not work. In all cases, they never built the circuit before contacting me!

TSB: Over the last 5 years, what do you consider to be the greatest technological innovation?

Mims: Smart phone technology is transforming the way many of us work, stay informed and contact others.

TSB: What’s your take on the smartphone craze?

Mims: My smart phone has become one of my most important instruments. It’s really not just a phone. It’s a hand-held computer that includes a phone.

TSB: What advice do you have for today’s DIYer?

Mims: Build stuff! Too many people are couch potato DIYers. They love to read about what real DIYers are doing when they could do be doing the same thing or even more. DIYers should also consider finding practical and scientific applications for some of their creations. That’s what I do, and it’s very fulfilling. For example, a simple sun photometer I built in 1990 has been used almost every day to measure haze and the total water vapor of the atmosphere. This simple instrument has been published in several scientific papers (with more on the way). It’s among the longest operating of any such instrument. I published basic details for this in a RadioShack comic book.

TSB: Where do you believe the DIY movement is heading?

Mims: The biggest and most important shift for the electronic DIY movement has been away from discrete component processors to microprocessors. The down side is that some DIYers have used a micro when a much simpler 555 would do the job. The upside is that programmability provides a virtually endless array of applications when the power of a micro is needed.

If you are looking to start on your own DIY project be sure to check out The Great Create movement. Show us what great creation you can come up with using RadioShack products. We would love to show what our most creative customers can do!

Be sure to check out your local RadioShack store or for the Forrest Mims’ books and our great products!

Learn more about Forrest Mims at his website:


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  • daniel

    Thank you for interviewing Forrest !!!

  • Michael Cheung

    I am looking for a solar charging system to be installed on my garage roof to trickle charge my Jeep battery which is parked in the locked garage for up to as long as 4 months unattended , without fear of overcharging that could damage the battery or cause fire hazard.

  • Edward Cheung

    I am 48 now, and have been a reader of Mr. Mims’ books all my life. I really enjoyed building circuits from his books as a child. Through college and graduate school, I always did really well in EE course, and now work at NASA. Several of my designs are in space on the Hubble Space Telescope, including the Wide Field Camera III. This is currently HST’s flagship science instrument.

    My favorite book of his is “Engineer’s Notebook”. It is full of hand drawn circuit diagrams, and I have referred to it countless of times. Its diagrams includes the LED scope Mr. Mims describes in this article.

    I would be interested in meeting Mr. Mims one day. Please contact me if that is possible. Thank you Mr. Mims for a life time of learning.

  • Joe Hughes

    Nice to hear from you,Forrest.Read your books years ago,but they are rare in Radio Shacks stores I’ve recently visited.I’ll buy them whenever they are available.I learned quite a bit from them.

    I’m just getting back into electronics.I bought microcontrollers and sensor circuits from Parallax.
    Thinking about building a model ocean racer with a etrex gps that I extract NMEA sentences with a Qbasic program I got from a Pc Interface Multimeter I bought from Radio Shack.The gps data should control the rudder and other motors with the microcontroller and transmit the data via internet or radio.

    The Qbasic program works fine with the etrex gps but I’m having a problem with eh Pc multimeter.Perhaps you have some advice about how to program the meter.

    In any event ,I’m glad to hear Forrest is well.From all his books I read he seems to be a long lost friend.Thanks,Forrest,for all you’ve done.JHughes

  • Gary

    Forrest Mims has been a virtual inspiration in print and now online for a long time! Kudos to The Shack for keeping the creative juices in the American spirit flowing with Mim’s writings!

  • sdudley

    I agree, thank you for interviewing Forrest. The man has been an inspiration for many years and has been a major influence to many of my own projects – couldn’t have done them without the mini-notebooks!

  • Todd Gordon

    Thanks for the inspiration.

  • Robert L. Jackson

    I have used “Getting Started in Electronics” as a “text” book for beginning “Tom Edisons” in my neighborhood. I am a retired EE and find Forest Mim’s booklets very interestng and valuable. They have starated several young men on life careers.
    Thank Yu, Mims and Radio Shack

  • Mike Ressl

    Dear Forrest,
    THANK YOU! I have worked in experimental physics research all my life, with several patents in opto-electronics to my name. When I want to check out a new idea by building a prototype, I always turn to your Mini-Notebooks first for ideas for the building blocks. Then I just go build it. I have a well worn, annotated set of 6 notebooks (RS CatNo 62-5010 (through -15)) that cost me $1.99 each – some of the best investments I ever made!! I loved the comment on the failures of PhD CP DIY’s.
    Ricky, Thanks for doing the interview!
    Keep up the great work!

    Best regards,

  • james rosenstein

    i couldn’t not find the unsubscribe button on your site. I want to be removed from your emails. Sorry.

    • Ricky Cadden

      James – sorry to hear that you don’t want to get our emails – hopefully you’ll change your mind in the future. For the meantime, if you open any one of our emails, there’s an UNSUBSCRIBE link at the bottom – that’s the best way to be removed.

  • Lee

    Thank you Forrest for the understanding of the fundamentals that you gave me years ago, as well as all of the pleasure that I had gotten when building all of those little projects.

    And after all of these years I still have the book with the yellow cover.

    Again, Thank you Sir..

  • Fred Hughie

    Yeah, I’m a fan from way back too. Great interview. All the fundamentals I learned from the green book (Getting Started in Electronics).

  • Trent Christy

    Thanks for all your books Forrest.
    I’m sitting here looking at a stack of 8 Engineer’s Mini-Notebooks and your Getting Started in Electronics book written in the Archer days.
    I’ve been enjoying them for years and continue to cherrish them.

  • Darryl Koon

    Hi Forrest, I’d guess that background in your picture above is up on Mauna Loa in Hawaii near where you visit each year to continue your scientific research. I’ve enjoyed your books for years and it’s a pleasure to see you up on the mountain each year. I saw your name in a Radio Shack email and couldn’t resist checking this out and submitting a Hello. I enjoyed reading this Q&A page.

  • Robert

    Do you reply to questions re multimeter reading I am testing a refrigerator light switch with both black&red probes touching switch dial will go to the right to zero with probes still touching the post I press the switch button & dial will go back to the left to zero would this indicate switch is good