Dew Controller – #1

Amateur astronomy is a big thing for me. I love looking at the wonders of the night sky while everyone around me is fast asleep. It helps me decompress from the stress of my day job and I find that it puts all of my “earthly woes” into perspective, once I get into the zone. I highly recommend you give it a go!

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Lab Tour

I know I like to tour other people’s labs, so I guess it’s only fair I presented mine. It’s nothing fancy and far less well equipped than some of the wonderful man caves people show on Dave Jones’ EEVBlog, but it gets the job done and I’m pretty happy with the setup as it is right now.

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Weller WTHA 1

I have been in the market for a hot air station for some time now. A bit of research quickly showed that many people recommend JBC stations. Sadly their price point is a bit above what I consider acceptable for my hobbyist use case, and since I am very happy with my Weller 81 soldering station I decided to go for the Weller WHA 900.

While browsing for it I saw that Weller had just announced a new line: the WTHA 1! A quick spec check later, I decided that I did not need the WHA 900’s foot switch and that the new unit had a much sexier design than the 900. I was sold, so I quickly placed my order…

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Bipolar Junction Transistors

Transistor types and polarities

Transistors are three-terminal devices capable of amplifying signals. They come in two broad classes, bipolar junction transistors (BJTs), and field-effect transistors (FETs). These notes are about BJTs.

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DC Load – #2

It’s prototyping time !

We will keep it simple: we’ll restrict ourselves to the basic schematic we proposed in the first part of this series, and we won’t worry too much about which specific op-amp and transistor to use. We’ll use whatever parts we find in the bin, after all this is about proving a concept. Once we get it working, we’ll hook the circuit up to the oscilloscope and have a look at what’s going on on the inside. Should be fun, let’s go! Read More →

Rohde & Schwarz HO3508 Logic Probe

I’ve been poking around digital circuits with my oscilloscope’s analog probes for over 2 years now and basically it works just fine.

But. (And this is a big but.)

As soon as you need to have a look at more than one or two signal lines (say you’d like to look at a bus) this setup gets messy real quick. The analog probes are big, long and unwieldy; and due to their weight they tend to shift your PCB around as soon as you look at them the wrong way. Not very ergonomic. On top of that my scope only has 4 analog inputs, making debugging of more complex digital circuits impossible.

But that’s not the only problem with analog probes.

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Foundations

Voltage and Current

Current (I) is the rate of flow of charge through a certain point in a circuit, it is measured in amperes. Voltage (V) between two points in a circuit represents the driving force that causes current to flow between them, it is measured in volts. Read More →

DC Load – #1

My home lab could definitively benefit from an electronic dummy load (EDL). I have a couple of projects on the way for which I could use one for testing purposes. One of these projects is a linear power supply, and I am sure most of you people know that hacking together something to simulate a half decent load only gets you so far. In addition, I have a plan to design a portable LiFePO4 power pack for my telescope mount where an EDL would come in very handy for testing purposes.

Google tells me that designing your own EDL is a common project for a hobbyist EE, so this should definitively be doable. Read More →