A bench power supply makes powering circuits easy and safe. Learn how to adjust basic controls like voltage. Finally, see how “current limiting” works (and why you should use it.) See how you can use built-in series or parallel tracking to increase a bench power supply’s voltage or current output. Last, if you are in the market for a power supply, do not forget to add some leads like mini-grabbers, alligator clips, and banana plugs.
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One of my early hobbies as a kid was collecting baseball cards. At every card show, I was on the lookout for the 1989 Ken Griffey Jr Rookie card, #1, from Topps. My collecting craze lasted until the baseball strike in 1994. Then I lost interest in professional baseball and its collectibles.
You’re asking, what does this have to do with electronics? Well, the Circuit Trading Cards from Arachnid Labs reminds me of the days I spent trading baseball cards. Instead of memorizing RBIs and Homerun counts, these circuit patterns trading cards teach you circuit basics.
The card stock used is of high quality, and each unique card has a durable feel. One side is the Arachnid Labs logo while the other is what I call the “information side.” The information side is one of three colors: Yellow (Analog), Blue (Digital), and Green (Power).
Rob ‘linear’ Arnold has put together a fantastic LED Series/Parallel Wizard. Not only will it calculate the current limiting resistor you need, it will draw a circuit diagram, and give you full statistics on power usage. If you are just getting started with Electronics, this is a great resource for learning about LEDs. Experienced users will enjoy a quick check of their math.
The array above is designed for some Blue LEDs I have laying around. I wanted them to run with 15mA which is well below their max, but still very bright. In this case 1/4W resistors should be fine and each should be 120 ohms. I should be safe hooking this array up to an Arduino since each LED will draw less than each I/O pin can handle AND total current draw is only 60mA.
Very Cool Stuff!
Electronics Weekly has invited Dale Cigoy of Keithley Instruments to talk about how capacitors work. Since capacitors are part of almost any Electronic circuit or project, it is a good idea to understand these basic components a little more. The article is titled “Seeing how capacitors work is invaluable.”
