The Engineering Octopus has launched a keyring with a difference: As well as helping you keep track of your keys, it doubles as a means to quickly test an oscilloscope — hence its name, the Oscilloscope Tester Keyring (OTK).
“All electronic engineers love to show off the fact that they are electronic engineers, and what better way 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 Engineering Octopus founder Max writes. “The OTK generates a pure, analog, 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!”