• EEVblog 1718 - Cheap 1GHz Oscilloscopes are Useless? • ($5 DIY 1GHz Resistive Probe) EEVblogNovember 14, 2025EEVblog,OscilloscopesComments Offon EEVblog 1718 - Cheap 1GHz Oscilloscopes are Useless? • ($5 DIY 1GHz Resistive Probe)4,515 Views Facebook Twitter LinkedIn What use is a 1GHz oscilloscope if it doesn’t have a high frequency active probe interface? • Well, there are several options including a cheap $5 DIY resistive probe.Practical demonstration of active FET probing vs Passive Probing vs DIY Resistive probing. • A lot of material extracted from videos 1367 and 1368 Forum:https://www.eevblog.com/forum/blog/eevblog-1718-is-a-cheap-1ghz-oscilloscope-useless-($5-diy-1ghz-resistive-prob/ 00:00 - What use is a cheap 1GHz oscilloscope if it doesn’t have an active probe interface?02:30 - Capacitive reactance and tip capacitance03:55 - High bandwidth passive probes04:59 - Active FET probes to the rescue, right?07:54 - DIY $5 1GHz Resistive probe09:02 - DIY resistive probe explained13:33 - Active FET probe example: Poor Grounding vs Good Grounding19:02 - $5 DIY Resistive probe vs $3k Active FET probe19:48 - What’s going on here? • The downside of resistive probes.21:10 - Resistive probes are more tolerant of grounding25:08 - Conclusion Podcast:Download
Article Summaries:
- EEVblog episode 1718 examines the limitations of inexpensive 1 GHz oscilloscopes that lack an active probe interface. The host demonstrates the differences between high‑bandwidth passive probes, active FET probes, and a $5 DIY resistive probe built from simple components. He explains the physics of capacitive reactance and tip capacitance, then compares the performance of the DIY probe to a $3 k active FET probe, highlighting issues such as grounding quality, signal integrity, and tolerance to grounding errors. The episode concludes that while the DIY probe offers a low‑cost alternative, it has trade‑offs that may make it unsuitable for certain high‑frequency measurements.
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