Can a 1µF decoupling capacitor be too much?

What happens when a breadboard Arduino skips a decoupling capacitor or two

1uF Decoupling Capacitor Circuit

To save time, breadboard pins or just lack of knowledge people try to skip adding eve one decoupling capacitor to a circuit. Either on IRC or in Forums you can almost always see it coming: “randomly, my circuit stops working” And then, “what do you mean a decoupling capacitor?” question.

While working on breadboard Arduino, I came across some unexpected measurements. Initially, the only capacitors on the breadboard were the two 22pF from crystal to ground and the capacitor connected to RESET for Auto-RESET.

Keep reading to find out what happen when I added a 100nF and a 1µF cap. A bunch of scope traces and surprising results follow.

Breadboard Arduino with no Decoupling Caps

Breadboard Arduino with no Decoupling Cap

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AddOhms Electronics Tutorials DVD Now Available

AddOhms DVD 1 Banner

When I was in elementary school, I remember Ms. Coker telling us we needed to memorize our multiplication tables because we wouldn’t always have a calculator.  Years later in college I was told, “learn to use the library, it’s not like you can carry the internet in your pocket.”

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Seems strange that I always carry 3 devices on me that do both.

Today a generation of people are growing up with the mass of all human knowledge available to them from birth. No formal education is necessary. And the only need is a modern device with WiFi.

However. Not all accessible information is equal. Which is why I created the AddOhms Electronics Tutorial Video series. Instead of teaching Electrical Engineering as an engineer to other engineers, I’ve created a series that uses simple language to explain electronics to anyone.  And now the growing YouTube series, is available for sale on DVD!

Keep reading to learn more about Volume 1 of the AddOhms DVD.

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(P.S.  The first batch on Tindie were hand made and include a special thank you…)

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The best 4 transistors to keep in your parts kit

When your project needs a transistor there are tons of choices.  Which makes answering the question “Which transistor should I use or buy?” a daunting task.  Fear not, before wading through spec sheet after spec sheet consider of these 4 general purpose transistors.  Every electronics enginerd’s toolbox should have a few of each.

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9V Batteries Suck — And why you shouldn’t use them.

Smoke detectors beep when their backup battery dies, which always seems to occur in the middle of the night (at least for me.) These backup batteries are usually a small rectangular 9V. They have become popular choices for electronics projects. If you need your Arduino project to last longer than a day, this isn’t the battery you want to use.  Here’s why.

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Unlike Speed Limits, Ohm’s Law isn’t a Suggestion

Ohm's Law Tutorial

Getting started with electronics always involves a discussion of Ohm’s Law. What is this mysterious sounding law and how can you use it when building electronic projects?  One the main uses for Ohm’s Law in your projects is to calculate the resistor value needed for a LED.  This article takes a look at what Ohm’s Law is and how to use it with LEDs.

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Electronics: Introduction to Breadboards

Soldering every circuit you build probably isn’t practical.  At some point you are probably going to want to use some type of temporary method to connect different components together.  One of the popular methods is using a breadboard.  This simple (and cool) looking device only needs a few instructions before you can begin

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AddOhms #6: Analog and Digital

It isn’t always clear what is meant by calling a device or a signal “analog” and “digital”.  This AddOhms tutorial explains the difference between analog and digital by using an analogy to clocks.  Old-school clocks with hands are a great example of “analog” while alarm clocks with digits as their display are an excellent example of “digital”.

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November 2013’s issue of Electronic Products features an article on the cover titled “Introduction to Polymer Capacitors.”  The author is, well, me. This article explains the differences between traditional MnO2-Tantalum and  Polymer-Tantalum capacitors.  Previously I explained these differences in the post on the fire hazard the Arduino GSM shield poses (due to improper derating).

You can find the Electronic Products article wherever magazines are sold or here:  Introduction to Polymer Capacitors.  Check below for links to high-resolution pictures.


Appearance:Introduction to Polymer Capacitors
Outlet:Electronic Products