Recommended · for some experience
#88: Cheap and simple TDR using an oscilloscope and 74AC14 Schmitt Trigger Inverter
Why people recommend it
Builds a simple fast-edge pulse generator from a Schmitt trigger inverter and uses it with an oscilloscope as a makeshift time domain reflectometer for cables.
Watch for: Useful for measuring cable impedance and velocity factor
In their words
If you want to see how to use a pulse generator as a TDR and/or build a simpler version that only creates long pulses, see this video (not mine).
Mattman944 on electronics.stackexchange.com, Jan 2026. CC BY-SA.
I should mention that the original tutorial/video by W2AEW from where I got the information for this circuit also has some overshoot, but not to the degree I have.
JYelton on electronics.stackexchange.com, Aug 2013. CC BY-SA.
Cheap and simple TDR using an oscilloscope and 74AC14 Schmitt Trigger Inverter
Biduleohm on electronics.stackexchange.com, Oct 2014. CC BY-SA.
