The 555 is a very popular chip, and for good reason. It is such a versatile timer. Learn about 555 measurements like how to measure the voltage divider inside the chip and what is going on with the signals in an astable multivibrator (clock) circuit. The key to a 555 circuit is connecting the threshold and trigger pins together. But, until you see the schematic and waveforms it may not be obvious why.

Active components like transistors, BJTs, MOSFETs,  and integrated circuits (ICs) make it possible to control circuits. This video explains the must-have NPN and PNP BJTs. For MOSFETs there are a couple of N-Channels and P-Channels to consider. Basic ICs include some digital logic stuff from the 7400-family as well as the venerable 555-timer to have on-hand. We did not forget Op-Amps either. Spoiler: We do not recommend the ua741!

Logic probes are great for debugging 7400 series logic chips and digital circuits. In this video, James makes a counter circuit and debugs each stage as he builds, with a Logic Probe. If you are wondering, “do I need a logic probe” this video shows how one can be used and even answers when you should consider buying one.

When you need to buffer the output of an R-2R ladder or an RC filtered PWM signal, an op-amp is a single chip option. Unlike a discrete NPN transistor like a 2n3904, there is a lot going on inside of an LM741—or any op amp for that matter.

What if you could look inside of the op-amp? Wouldn’t it be cool to see how many transistors make up these small chips?

Put your electron microscope away. The XL741 from Evil Mad Scientist Labs is perfect for the job. I built one of these super fun solder kits and compared it to a real 741.

After fighting bugs, bad connections, and burned out chips your project is working–or even done. The next step? Record a video, edit it, and upload it to YouTube.

Too many steps? Then maybe you just want to do a Periscope demo. Within seconds, you can be broadcasting your project to the world.

This past weekend I tried my first couple of scopes. The first Periscope “demo” was me soldering together a Three Fives from Evil Mad Scientist Labs. The others periscope demos were 3d printing related.

When it comes to a hardware project demo, I see some challenges. Check out these five things to watch out for and, if you’re interested, you can watch my soldering Periscope demo.