KONIGEVA Capacitor - Variable, Single, 365 pF, CW Rotation

Arrived (very quickly!) just as described and rotates smoothly 180 degrees, varying the capacitance from 0pF to 362pF per my LC meter.A standard 1/4” shaft (round with a set screw) plastic (or other nonconductive) knob is highly recommended.I used this capacitor to build a simple crystal radio on a wooden board with my kids. Worked GREAT!Couple of things that surprised me and hopefully will save you some grief and help you make best use of this nice capacitor...1) Note that all four terminals are one node (one side of the capacitor) and the metal frame is the other node. Maybe this was obvious to most, but it took me a bit to discover. If I hadn't had an LC meter to figure it out, I'd likely have assumed that the two terminals on one side were node1 and the two on the other side were node2... and then spent lots of time wondering why my circuit wasn't working!2) I mounted the capacitor to the board using the 4 #6-32 threaded holes on the bottom of the capacitor. I discovered that when the screws are tightened, the wood applied upward pressure to the two perpendicular terminal boards on either side (they extend just slightly below the metal frame), thus deforming the stationary plates of the capacitor which prevented the shaft plates from rotating without friction. I don’t think this is a design flaw at all but, clearly, if using the threaded mounting holes on the bottom, a small spacer (only about 1/16" or even 1/32”) is required between the metal frame and the wood (within/between the edges of the terminal boards) to prevent pressure on the terminal boards from the wood. FYI, after the initial deformation I was able to remedy the problem by gently shifting the terminal plates back down to their original position with a pair of needle nose pliers and the shaft now rotates freely again. (Sorry if that description isn’t clear; hopefully it will make sense once you have the capacitor in-hand and can avoid the mistake I made.)

The capacitor was very well packed and arrived perfect. It is a quality item.

Heavy steel U-frame, ball bearing in the front (greased), spring steel grounding wiper in the back, brass 1/4" shaft, and phenolic insulators. Four mounting holes in the bottom and 2 in the front are tapped 6-32, other are untapped. Smooth rotation, solid stops. Mine measures 15-386 pF. Note that the connections are between the frame and one of the four solder lugs; all the lugs are connected to the stator.-Gary NA6O

Works great

I was wanting to build a QRP HF antenna tuner for the amateur radio bands from 160m to 6m and did not want to use the cheaper polyvaricon capacitors which have high losses, limited life and low power capabilities. I found several sources for these 365pF air variables and at the time I ordered them the Amazon price was competitive with ordering them direct from China.I designed a Pi network antenna tuner as shown in the photo which uses 2 of these capacitors and a series of fixed switched inductors and I am able to match anywhere from 25 ohms to 500 ohms over 1.8MHz to 54MHz with this unit.I did notice after my last order the price virtually doubled. I don't know if this is due to Tariffs or not, but it looks like I'll have to go direct to China to get these now. For $25 apiece I can get a US sourced air variable with 8:1 planetary gearing.

This capacitor is sturdy and nicely built. It turns very smoothly and has enough heft to it to give the impression of "something real", compared to flyweight electronic components. Using my very poor eyes to judge plate spacing, they look like a little less than 1/32 of an inch apart. Assuming low humidity, I would be very hesitant to subject this to greater than 1kV, and in humid locations, much less. For use in a manual antenna tuner, its application is limited - no end- or near-voltage-node- fed antennas. It should do well for low power on any centerfed, even if fairly far from resonance.

I used these (I bought 2) for building a TA7642 based AM radio set. It works perfectly.

Wow! I didn't know you could find these new anywhere, or at all for that matter. A throwback to the "inbetween" of when radio really was then, and a bit before now! Nicely built, smooth-tuning, all in all a crystal set builders dream. Also great for pre-amps, and preselectors. Wherever a 365-400pf variable is needed. these will do the job, and cared for correctly will last many lifetimes! Thanks to Amplified Parts