# Digital Circuits 2: Some Tools ## Overview ![](https://cdn-learn.adafruit.com/assets/assets/000/052/652/medium800/components_tools.jpg?1522367184) When we work on electronic circuits, there are some tools that get frequent use. Things like multi-meters, oscilloscopes, and waveform generators. Working with digital circuit has some use for those, but brings with it different requirements that require different tools. We'll have a look at some of these. These are fairly simple and can be made quite easily. ## Update: When I designed, prototyped, and even when I laid out several revisions of the PCBs, my thought was always "these will be useful when people are playing around with the TTL chips I'll talk about in this guide series." Then it hit me. These are incredibly useful whenever you're hacking on any **5v microcontroller board**. That includes - ATmega328 boards such as Arduino UNO, Nano, Pro Mini - ATmega32U4 boards, such as the Arduino Leonardo, Micro,  - ATmega2560 boards such as the Arduino Mega2560 If you want to use the I/O boards with a 3.3v microcontroller board, you generally can't do it directly. Instead, you have to use a level shifter. The majority of Adafruit's breakout boards have level shifters builtin, but these I/O boards don't. You are in luck, though: Adafruit sells a levelshifter breakout that can be used between your 3.3v board and the I/O boards.  - [Next Page](https://learn.adafruit.com/some-digital-tools/logic-probe.md) ## Featured Products ### Premium Male/Female Raw Jumper Wires - 40 x 6" [Premium Male/Female Raw Jumper Wires - 40 x 6"](https://www.adafruit.com/product/3633) Our **Raw Male/Female Jumper Wires** are perfect for making a custom jumper wire sets for wire harnesses or jumpering between headers on PCBs. These premium jumpers are a little over 6", almost 8" (about 200mm) long and come in a 'strip' of 40 (5 pieces of the ten rainbow... In Stock [Buy Now](https://www.adafruit.com/product/3633) [Related Guides to the Product](https://learn.adafruit.com/products/3633/guides) ### Small Single Row Wire Housing Pack for DIY Jumper Cables [Small Single Row Wire Housing Pack for DIY Jumper Cables](https://www.adafruit.com/product/3145) Are you frustrated by the lack of customization options for your jumper wires? Look no further! Compatible with both male and female wires, these fully customizable wire housings bring DIY to a new level, giving you... In Stock [Buy Now](https://www.adafruit.com/product/3145) [Related Guides to the Product](https://learn.adafruit.com/products/3145/guides) ### Heat Shrink Pack [Heat Shrink Pack](https://www.adafruit.com/product/344) Heat shrink is the duct tape of electronics, it keeps your stuff all safe and kept together. Especially when wiring and soldering, use heat shrink to add mechanical strength to cables. We use this stuff all the time and having a zip-lock bag of all the possible sizes is super... Out of Stock [Buy Now](https://www.adafruit.com/product/344) [Related Guides to the Product](https://learn.adafruit.com/products/344/guides) ### Tactile Button switch (6mm) x 20 pack [Tactile Button switch (6mm) x 20 pack](https://www.adafruit.com/product/367) Little clicky switches are standard input "buttons" on electronic projects. These work best in a PCB but [can be used on a solderless breadboard as shown in this tutorial](https://learn.adafruit.com/adafruit-arduino-lesson-6-digital-inputs?view=all). The pins are normally... Out of Stock [Buy Now](https://www.adafruit.com/product/367) [Related Guides to the Product](https://learn.adafruit.com/products/367/guides) ### Breadboard-friendly SPDT Slide Switch [Breadboard-friendly SPDT Slide Switch](https://www.adafruit.com/product/805) These nice switches are perfect for use with breadboard and perfboard projects. They have 0.1" spacing and snap in nicely into a solderless breadboard. They're easy to switch no matter what size fingers you have, but not so easy that they'll get flipped by accident. Work great as... Out of Stock [Buy Now](https://www.adafruit.com/product/805) [Related Guides to the Product](https://learn.adafruit.com/products/805/guides) ### Diffused Green 5mm LED (25 pack) [Diffused Green 5mm LED (25 pack)](https://www.adafruit.com/product/298) Need some indicators? We are big fans of these diffused green LEDs, in fact we use them exclusively in our kits. They are fairly bright so they can be seen in daytime, and from any angle. They go easily into a breadboard and will add that extra zing to your project. - Pack of 25... In Stock [Buy Now](https://www.adafruit.com/product/298) [Related Guides to the Product](https://learn.adafruit.com/products/298/guides) ### Diffused Red 5mm LED (25 pack) [Diffused Red 5mm LED (25 pack)](https://www.adafruit.com/product/299) Need some indicators? We are big fans of these diffused red LEDs, in fact we use them exclusively in our kits. They are fairly bright so they can be seen in daytime, and from any angle. They go easily into a breadboard and will add that extra zing to your project. - Pack of 25... In Stock [Buy Now](https://www.adafruit.com/product/299) [Related Guides to the Product](https://learn.adafruit.com/products/299/guides) ### 8-channel Bi-directional Logic Level Converter [8-channel Bi-directional Logic Level Converter](https://www.adafruit.com/product/395) Because the Arduino (and Basic Stamp) are 5V devices, and most modern sensors, displays, flashcards, and modes are 3.3V-only, many makers find that they need to perform level shifting/conversion to protect the 3.3V device from 5V. Although one can use resistors to make a divider,... In Stock [Buy Now](https://www.adafruit.com/product/395) [Related Guides to the Product](https://learn.adafruit.com/products/395/guides) ## Related Guides - [Level Shifting 3.3V microcontrollers and NeoPixels](https://learn.adafruit.com/neopixel-levelshifter.md) - [reef-pi Guide 3: Temperature Controller](https://learn.adafruit.com/reef-pi-guide-3-temperature-controller.md) - [Windows IoT Core Application Development: Headed Blinky](https://learn.adafruit.com/windows-iot-application-development-headed-blinky.md) - [Adafruit QT 3V to 5V Level Booster Breakout](https://learn.adafruit.com/adafruit-qt-3v-to-5v-level-booster-breakout.md) - [DIY Pi 400 Keyboard Case](https://learn.adafruit.com/pc-keyboard-case.md) - [How To Take Great Photos of Your Projects](https://learn.adafruit.com/how-to-take-great-photos-of-your-projects.md) - [Computer Perfection Synthesizer](https://learn.adafruit.com/computer-perfection-synthesizer.md) - [Naughty or Nice Machine](https://learn.adafruit.com/naughty-or-nice-machine.md) - [Zelda Echoes Of Wisdom Tri Rod](https://learn.adafruit.com/zelda-tri-rod.md) - [MiniPOV4 - DIY Full-Color Persistence of Vision & Light-Painting Kit](https://learn.adafruit.com/minipov4-diy-full-color-persistence-of-vision-light-painting-kit.md) - [Wearable miniPOV4](https://learn.adafruit.com/wearable-minipov4.md) - [Bedazzler](https://learn.adafruit.com/bedazzler.md) - [Adafruit IO Basics: Color](https://learn.adafruit.com/adafruit-io-basics-color.md) - [Infinity Mirror Valentine's Candy Box](https://learn.adafruit.com/infinity-mirror-candy-box.md) - [Arduino Lesson 2. LEDs](https://learn.adafruit.com/adafruit-arduino-lesson-2-leds.md)