MOTOKU 2X Copper Adapter 50Ohm 38.5mm Insert Type BNC Feed Through Terminator

These are an inexpensive and high quality way to terminate your connections into your oscilloscope or other test equipment at 50 ohms. I prefer these to using my internal 50 ohm resistors in my oscilloscope just in case I go over voltage. I'd rather burn one of these than the front end of my very expensive scope! These actually have a decent low power rating. I view it has cheap insurance!

It works as specified.

They work as desired for on cheap oscilloscope which lacks built-in 50-ohm termination mode. A DMM confirms they're 50 ohm. I got these on a recommendation from another reviewer, as one of the better options for having appropriate impedance at a wide range of frequencies, but really I don't have the equipment or expertise to evaluate that myself. The packaging was not good: a little cardboard box, roughly 5cm x 7cm x 11cm, the two little metal adapters inside, and no bubble wrap or wadded-up paper or anything else, so they had plenty of space to knock around against each other in shipping. They came through fine, maybe I was a bit lucky.

These work great and they measure out right at 50 ohms. Great deal. I ended up grabbing a few, just so I'd have them.

They are of decent quality and about 2% tolerance on DC Ohms. Have not tested frequency response. Bought a second set just to have around as a lot of these out there are often junk. Absolutely needed when plugging different kits to the oscilloscope in order to avoid reflections.

Swept each of these (2 in a pack) up to 1.5 GHz and they held up well. The ones I received should be usable approaching 23cm territory. These are only good for low voltages and low power applications. Really, they are only mediocre terminators. The high rating is for the bang for the buck. Haven't found any better that are not also an order of magnitude more expensive. Returned the black plastic cheap version of these as they were wildly out of claimed specification and had a very poor response on the VNA useful up to maybe 500MHz. Using those proceeds to order another set of these.

These 50 ohm feed-through terminators work nearly as well as those from Pomona at less than a tenth of the cost. Measured with an HP VNA with one end open, the S11 return loss was better than -20 dB up to 680 MHz and better than -10 dB up to 1500 MHz -- and very smooth. See attached test setup photo and S11 chart. This is worse by just a few dB than the Pomona 4119-50 below 1 GHz. Note that the proper way to test a 50 ohm feed-through terminator is to leave one end open, as was done here. Don't connect it to an oscilloscope input when characterizing its performance, even if that's how it will be actually be used: above a few tens of MHz, a typical 1 Mohm (nominal) scope input's capacitance (generally around 18 pF) will dominate, and not even the best feed-through terminator in the world would look good on the VNA.

Five bucks for a 50 Ohm terminator is a great deal. Handy to keep a couple around. I took off one star because the Amazon image shows "50Ω" etched into the body of the terminator but the ones I received were unlabeled. I added a Brother label to each to make up for the deficiency.

廉価にオシロスコープ用のフィードスルー型の50 ohm ターミネーターが入手できて良かったです。 ちゃんと使えます。