All electronic engineers love to show off the fact that they are electronic engineers, and what better wat to do that than with a keyring! Not only will the bare electronics be noticed by many, it's also a fully functional oscilloscope tester!

The OTK generates a pure, analogue, sine wave (via a Colpitts oscillator) at approximately 10MHz (+/-2MHz). It has a DC offset, which allows you to test almost all functions of a oscilloscope, and carry it with you everywhere you go! It's battery powered (included!) via a CR2032 watch battery. Or, should the battery go flat on you, it also has a micro USB port so that you can use the oscilloscopes USB port (or a power banks).

But my oscilloscope has a square wave generator, I hear you cry? indeed, this is true, but, firstly, it doesn't fit on a keyring! Secondly, you need probes to test with that! Where the OTK really shines is for those of you who love to repair / buy oscilloscopes. More often than not, they're not supplied with probes, and this quick and easy tool can be taken with you to viewings. You simply plug it into the BNC connector, and test it out!

Here's just a few things I use mine for:

* DC / AC / GND switch test
* CRT Intensity

* Horizontal / vertical positioning

* Time base issues

* Volts per division issues

* Single shot trigger modes

* Triggering issues

And I'm sure there's plenty more if you're creative!

I sell them through Tindie, so the price fluctuates with the dollar/pound conversion. Any questions, feel free to drop me a message on the live chat!


The Oscilloscope Tester Keyring©, also referred to as OTK, is not designed as a substitute for reference testing, and is designed as a quick initial check of an oscilloscope, or similar equipment. The sine wave generated is approximately at the stated frequency of 10MHz.


The products have been cleaned with IPA and Flux-OFF, while every effort has been made to ensure no residue of either remains, it may be possible that some is left. Please ensure suitable handling.