On every page of my blog, you might notice a chat window. If I’m not busy, we can chat in real-time. If not, the messages come to me by email. Here’s one I got from Matt the other day:
Let’s talk a bit about how (and why) you would use a P-Channel MOSFET. Matt, and he’s not the only one, is probably asking this question based on the “myth” that P-Channel MOSFETs require “negative voltage” supplies.
Keep reading for how-to use only positive voltage in this p-channel MOSFET tutorial.
What part is the most important part in building a project? All of them! Okay, bad joke. Selecting the right parts or components for a design is an area where both new hobbyist and veteran engineers struggle. The wide variety of devices make it almost impossible to know if you are selecting the right one.
Looking at a curated List, using component search engines and browsing DIY shops are how I tend to find parts for my projects.
You might want to bookmark these some of these sites so you can use them next time you’re stuck on how to find parts for your project.
The funny thing about schematics is that they are much easier to draw than they are to read. There are many common circuits. When an experienced engineer looks at them, it’s like a second language. When someone less experienced looks at them, it looks like random lines and symbols thrown together at the last-minute. (Or maybe that’s just the schematics *I* draw.)
Other than reading Schematic Symbols themselves, one of the basic skill necessary to read a schematic is recognizing series and parallel circuits.
In short if the same current flows through all the parts, they are in series. While if current has different paths, they are in parallel. Keep reading to dive into this tutorial on how ohm’s law applies to series and parallel circuits.
Earlier I posted a PCB Checklist of items to double-check when sending your board out to a fab. The Dangerous Prototypes blog pointed to a 3D EAGLE PCB tool from a Bulgarian-based developer called Cytec that takes an EAGLE BRD file and renders it in 3D for you.
The example board I have above is a render of my MSO Demo Board. And I have to be honest, it looks much like that one!
I am not a fan of relying on the Autorouter in EAGLE — or any PCB CAD software for that matter. When laying out a board, I’ll use the autorouter to get an idea if the part placement is going to work or not. In this case, I was reminded how much autorouters suck! Even after running for while, the autorouter could only route up 50% of the nets (signals).
As Chris Gammell‘s T-Shirt Says, Never Trust The Autorouter.
It only took me about 20 minutes to start over and finish the manual layout. I still want to clean it up a little, but over all, I beat the Autorouter.
In January I visited Tokyo on my annual work trip. While there, I ran over to Akihabara to check out a used media store called Traders. The multi-level store (like all those in Tokyo) sold used video games and movies. Each floor featured different platforms. My favorite was the 2nd floor which was all retro 8, 16, and 32 bit systems. Piles of Famicoms (NES), Super Famicoms (SNES), Mega Drives (Genesis), and other systems were all around. In the middle of the floor were racks of cartridges.
While there I picked up a couple of Rockman (Mega Man) carts, Super Mario brothers, and even Adventure island.
A US-based NES can play Famicom games since the basic hardware is the same. However, the pin outs are slightly different. Also, US-based NES systems look for a lock-out ship (CIC) that Famicoms don’t have. Fortunately I ran across a project that uses the ATtiny (AVRCICZZ) to emulate the lockout chip. So armed with that and some pinouts, I’ve created an adapter.
Keep subscribed, after a few more touches, I’ll post the EAGLE files as an Open Source Hardware (OSH) project.
