…and the order from DigiKey

Ok. Today was THE mail day. I’ve received both my electronic parts orders, the one from RF Parts and the one from DigiKey, that I placed several weeks ago (but had some issues with a couple of backordered items). Ta–Da ! This is it:

A lot of bags and goodies. Not to mention the pleasure of sorting these out, I could hardly wait to finish my day job and get back to unboxing all these. I was a bit concerned because I have never ordered some of these parts before. Quite not sure what to expect. Thus, there were some pleasant surprises. And, again, the old saying you get what you paid for is very, very true. Let me highlight the main points.

Cables. Pomona Cables.

I needed those zoo bad ! I went on the DIY road initially, trying to build all my interconnect cables. I used regular RG58 cable and I was soon to discover that the cable is much less to be blamed for problems than the crappy BNC connectors that I bought in local stores. These are so low quality that the metal part is not even machined to the specs. They just rattle in the scope BNC jacks. One can wonder how could these be commercially viable, but there must be many morons like me that bought that cheap shit. Never again. So I got myself some quality Pomona cables:

It is a pleasure to use these. Perfect fit with my scope BNCs. The cables are 6 and 12 inch long (12.5 and 30 cm), rather on the short side. But my workspace is very crammed so I preferred shorter cables over long ones. All are RG58C/U 50Ω, ideal for most test and measurement applications, RF transmission systems and Thinnet LAN applications (see here for specs from Pomona).

Moreover, I also bought a pair of banana–terminated mini grabbers, for my lab power supply. Talking about cheap things, my previous mini grabbers lost their bananas. 😀 I mean, those literally went apart. Crappy Chinese shit. I assume there is also good Chinese shit. But those were crappy Chinese shit.

PCB mounted SMAs

For some weird reason (price ?), no edge–mounted SMAs can be found locally:

These are not cheap, though. Actually one piece costs more than a PD84001 Power RF LDMOS, or roughly twice as much as a Bourns rotary encoder. But these are genuine Molex, are made of solid brass with beryllium core, can be used for applications up to 18 GHz, and are designed to be edge–mounted on 1.68 mm thick FR4 PCBs (or .066″). By the way, a word of caution here. When you are looking into buying these, take care about the specs. There are many types of edge–mountable SMAs fitted for specific PCB thicknesses. Before buying, check your project’s PCB thickness, otherwise you might burn a lot of money on under– or oversized SMAs.

Rotary encoders

Difficult to find here too:

 

Did not have too much experience with these, but I have pending a dual–rail/ voltage supply project.  thus I ordered two different types: the Bourns (first photo) are 2–bit quadrature Gray Code and the double–T (second photo) are 2–bit ordinary Gray–code rotary encoders. Moreover, the TT encoders are supplied with a push–pull switch. For more on encoding, see links below. I have to put these to good use, but first I will build some simple Arduino projects to get more insight into their theory (and practice) of operation.

Dual–gate MOSFETS

Ok, this is the last one for today’s highlights. NXP BF998 Dual–Gate MOSFETs:

There is a guy, Stephan0719, that has some cool videos on dual–gate MOSFETs. He displays some very nice, simple projects. Unfortunately DigiKey availability of through–hole dual–gate MOSFETs is zero, so I had to order SMDs instead. But these will do. With some care on the soldering side, I can even use some home-brew PCBs.

There were many other goodies in the bag. Like an AD9911 DDS from Analog Devices (500 MSPS Direct Digital Synthesizer with 10-Bit DAC) for my RF signal generator, LM334 constant current source for the same power supply project, some FTDI USB interfaces (including a high–speed FT2232HL) to enhance my understanding of USB communication and driver programming, a bunch of P– and N–channel JFETS (impossible to find here), some crystals and a secret project. 😉

However, I procrastinate over this DigiKey order for more than a year. I put several projects on hold because I did not have the right and needed parts. No more excuses now. 🙂 I have to get back to all these projects and finalise them. Stay tuned. More [hopefully interesting] things to come on alauda.ro.

Further reading

• Wikipedia pages about Gray Code
• Contacting encoders from Bourns
• NXP dual–gate MOSFETs parametric search
• Wikipedia page about Multigate Devices