#88: Cheap and simple TDR using an oscilloscope and 74AC14 Schmitt Trigger Inverter

This video is a follow on from my previous video that discussed how to measure the length and impedance of coax using an oscilloscope and an pulse generator. This previous video goes into more of the theory and the different measurements you can make. It can be found here:    • #37: Use a scope to measure the length and...   However, this video showed the use of a pulse or function generator as the signal source. The problem is that most inexpensive generators won't have a fast enough risetime to be able to resolve shorter cables or finer precision in the measured length. This video shows a very inexpensive circuit that you can build that has a very fast rising/falling edge speed, making it easy to more precisely measure the cables. It is based on a 74AC14 Schmitt Trigger Inverter chip and a handful of passive components. One of the six inverters is used as an oscillator which drives the remaining 5 inverters in parallel to drive the coax under test. More detail regarding the Schmitt Trigger circuit can be found in the video uploaded immediately prior to this video:    • #87: Schmitt Trigger Oscillator / Tutorial...   This video is shot in HD

#286 which is faster 74HC14 or 74AC14
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#286 which is faster 74HC14 or 74AC14

#90: Measure Capacitors and Inductors with an Oscilloscope and some basic parts
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#90: Measure Capacitors and Inductors with an Oscilloscope and some basic parts

#167: How a Diode Ring Mixer works | Mixer operation theory and measurement
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#167: How a Diode Ring Mixer works | Mixer operation theory and measurement

#323: Measure length of coax, etc. with your scope, a battery and a resistor - simple TDR
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#323: Measure length of coax, etc. with your scope, a battery and a resistor - simple TDR

EEVblog 1718 - Cheap 1GHz Oscilloscopes are Useless? ($5 DIY 1GHz Resistive Probe)
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EEVblog 1718 - Cheap 1GHz Oscilloscopes are Useless? ($5 DIY 1GHz Resistive Probe)

Never buy solder stencils again
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Never buy solder stencils again

#394: Oscilloscope Best Practices - some of the most common issues and tips
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#394: Oscilloscope Best Practices - some of the most common issues and tips

EEVblog #306 - Jim Williams Pulse Generator
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EEVblog #306 - Jim Williams Pulse Generator

Ferrite Beads Don’t Do What You Think
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Ferrite Beads Don’t Do What You Think

Something is jamming GPS over Europe. Here's what we found
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Something is jamming GPS over Europe. Here's what we found

TA-0440: Leo Bodnar - Fast Risetime Pulse Generator 30ps LBE-1321
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TA-0440: Leo Bodnar - Fast Risetime Pulse Generator 30ps LBE-1321

The Fascinating Story of Tektronix, The Oregon Engineers Who Reinvented The Oscilloscope
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The Fascinating Story of Tektronix, The Oregon Engineers Who Reinvented The Oscilloscope

#122: Electronic Circuit Construction Techniques: review of some prototype circuit building methods
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#122: Electronic Circuit Construction Techniques: review of some prototype circuit building methods

Oscilloscope Basics, Part 1: Discussion, Y-Axis (Voltage) Controls, Probe Calibration
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Oscilloscope Basics, Part 1: Discussion, Y-Axis (Voltage) Controls, Probe Calibration

The Best Cable - Wire For Audio? Let's Look Closer!
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The Best Cable - Wire For Audio? Let's Look Closer!

#396: Demystifying Oscilloscope Triggering - what it does and how to use it
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#396: Demystifying Oscilloscope Triggering - what it does and how to use it

The most useful tool ever for electronics repairs - (PWJ212)
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The most useful tool ever for electronics repairs - (PWJ212)

Reinventing Entropy | Compression is Intelligence Part 1
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Reinventing Entropy | Compression is Intelligence Part 1

Once You Understand it, You Will Think Everything Else is Silly - Toyota E-CVT
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Once You Understand it, You Will Think Everything Else is Silly - Toyota E-CVT

#203: Schmitt Trigger Oscillator revisited | TDR | Measure Capacitors and Inductors
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#203: Schmitt Trigger Oscillator revisited | TDR | Measure Capacitors and Inductors