 Okay, this week's great search by DigiKey and AdaFruitLadyAda. What is the great search this week, AdaFruit? Okay, so this week we're going to look at RF capacitor kits. It's a handy thing which I don't have and so I was actually looking for one today anyways to purchase. So let's go to the overhead. So I was chatting with Unexpected Maker about the ESP32S3 and one of the things they mentioned is that they're sending us these new boards, the ones that we put in that have a better RF pie network and that actually gave me a hint to understand why my ESP32QD pies weren't working. I thought that the RF signal was too strong but it actually turns out I think the pie network is mistuned. And he mentioned like, oh yeah, I just had to kind of try a couple of different values and do some math and do some analysis and use a VNA which I'm totally into but before you hook up your VNA and after doing the math and while you're doing the VNA tuning, what you want to do is be able to swap out the pie network which is usually made up of inductor and two capacitors and the inductor and the two capacitors are like very small values and they're very precise. Usually the capacitors are like one to four picofarads, maybe five picofarads and the inductor is usually like a nano Henry or two or three. So having a kit because you want to try multiple values and the capacitors can have some variation so you're not going to get try like 2.2, 2.3, 2.4 because it's going to be plus or minus 0.25 picofarad anyways variation per component and on the PCB and depending on you know humidity and stuff. But you don't want to try very close values and see if you can tune your antenna and your network as close as possible so having a you know you could buy strips of tape but it's better if you can just get the kit that gets you all of them. So why don't you go to the computer in that way, ay? Sure. I'm going to go to the computer and just a sec. Got a bunch going on today. That's right. Okay, that's why I can go to here and here. You can keep on top of yourself. So I just searched for capacitor kit. This is the NPI. Cool radar. So DigiKey has a bunch of resistor and capacitor kits available both through hole and surface mount. This time we're just going to look for the capacitor kit and there's a couple things that I'm going to be looking for. So first up, let's go only for active and in stock right now because I'm only going to buy one and I just want to buy whatever, you know, I want to make sure they have it. I want to make sure it's an SMT component. I don't want through hole because I want, you know, the small capacitors they have, you know, electrolytic cap kits that are like, you know, every big value or ceramic. Next up, so the capacitance range is a little bit tough to go through. I mean, I definitely don't want these larger ones. But it's also like they're kind of intermixed like there's a start and end. So what I did instead is first I went to the package and I don't want a package range. I only want O402 because O402 is a very common small enough to not have, you know, high as effects but large enough that you could hand solder them if you wanted to. Some people use O603 that's also fine. I tend to use O402 for RF signal stuff. Don't forget that there is the Imperial O402, which means the metric is 10.05. And by selecting that small size, it actually limited the ranges already because it's like you're not going to get, you know, a 10 microfarad cap in O402. And then with tolerance, what I normally would want is to only pick C0G or NP0 tolerance, but they don't have that here and so they do this by like percentages and stuff. So what I want is pretty much anything that's, you know, I don't want it to be 20%, it should be 0.25% or less tolerance variation. Now I can actually look at the capacitance ranges. So they have one that's 0.05 picofarads to 0.075, that's too small. They have 0.1 to 22, which is kind of small, but that's still within my range. I want kind of like 1 to 10. This range looks good. This one's too big and this one starts too high. So, you know, these two are too low and these two are too high. So like this is a nice start. So let's apply and see what's available. So there's a couple of ones available. Not surprisingly, there's ones that are from each company. So Murata, you know, makes a kit point, you know, it's C0G, you can see in the photo, 0.1 picofarad to 5 picofarad. That's a nice looking kit. I actually thought that there's a couple kits I thought that were nice, but this one was not too bad. It had some, it kind of has a mix of both small. I like doing the lookover because you can see it goes from 0.2 picofarad, 0.3, 0.5, 0.7, 0.9, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.4, 2.7, 3, 3.6, 4.3, 4.7, 5, 6, 7, 8, 10, you know, so it's like, it's kind of like larger, goes to 30 picofarad. This one has many, many more values. It has like every 0.1 or 0.2 value up to 6.8 picofarads. This is actually the kit I ended up thinking I'm going to get. Another thing about this kit that I like is it only goes up to 6.8 picofarad. And I tend to be dealing with 2.4 gigahertz, which is like the range I want. What I would first do, if you're not sure, if you're using other frequencies, look at a common Pi network for that antenna, like 50 Hertz-ish, and see what the range of capacitor values are, because you might need larger caps as you go to lower frequencies. These are all good kits. Some are going to be, like this one also looks really great. This one's a Digi-Key brand one from Tyro-Yudin. 25 values, 10 pieces each. 10 pieces is a smallish number, I think, just in case you're doing a lot of soldering and desoldering. Because honestly, the O402s, I kind of lose half of them. Like I grab them with my tweezers and they fly off. So that said, I think this one's a good one, S402TS. So I would pick this one, grab one of these, and then I'm going to use this as I tune this Pi network on the ESP32 Pico. All right, and that is this week's Great Search.