TNP #56 - Variable Vacuum Capacitors Exist! Analysis & Experiments with Multi-kV Vacuum Tube Caps
18.7K views
December 15, 2025 10:30 PM
In this episode Shahriar takes a look at some fascinating variable vacuum tube capacitors. These devices are mechanically adjustable to achieve a wide range of capacitance values. Despite the narrow gab between the parallel cylinder plates, they support up to 10kV operation.
The internal structure & principle operation of the capacitors are covered. A Zurich Instruments MFIA Impedance Analyzer is used to measure the capacitance values across their tuning ranges. One unit has a DC motor assembly attached to the adjustment point which allows the capacitor to be electronically adjusted. Lastly, a high-voltage DC power supply is used to demonstrate that the capacitor can easily withstand its rated 5kV operation.
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TSP #270 - I Can See Sound! FOTRIC TD2 Acoustic Camera Theory, Teardown, Review & Experiments
53.1K views
November 9, 2025 4:40 PM
In this episode Shahriar takes a look at an acoustic camera. These instruments leverage an array of microphones in interesting arrangements to perform acoustic beamforming and localize the source of sound. Furthermore, they combine this information with a visual camera and produce a scene image where sound sources can easily be identified. Given the fairly broad frequency range (2kHz – 65kHz) of the FOTRIC TDS, it can be used in a wide range of applications:
https://www.fotric.com/td2-acoustic-imaging-camera
This review is organized as follows:
00:00 – Introductions & instrument overview
01:21 – Detailed teardown, system & circuit analysis, theory of operation
13:41 – GUI overview, built-in functions, frequency discriminations, surprise lab noise source
19:03 – Controlled frequency & source tests, audible & low-frequency tests, multi-source
26:15 – Detecting leaks, mechanical noise detection
28:24 – PC software post-analysis
29:28 – Concluding remarks
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TSP #269 - Wonderful Complexity of X-Ray Dosimeter Badges! Teardown, Analysis & Theory of Operation
10K views
November 1, 2025 9:37 PM
In this episode Shahriar explores the incredible complexity of x-ray dosimeter badges. These badges are critical in exposure safety measurements and are used by millions of professionals. But how do they work? The x-ray image of the badge reveals its internal structure, x-ray energy discrimination techniques as well as the TLD detectors. The end-to-end operation of the badges are discussed in details as well as the measurement methods.
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TSP #268 - Radio Over Fiber Magic! Optical Link Teardown, Characterization & Measurement Techniques
20.4K views
October 31, 2025 4:24 PM
In this episode Shahriar presents a deep dive into direct detection optical links. The video covers a wide range of topics from detailed module teardown, optical semiconductor discussions, free-space optic interconnect, theory of operation as well as comprehensive characterization of the end-to-end system behavior. Key chapters of the video are organized as follows:
00:00 – Theory of operation, block diagrams & instrument architecture
08:48 – Detailed teardown, optical module analysis, high-magnification imaging
24:32 – Optical link characterization, Siglent instrument ecosystem, radio-over-fiber demonstrations
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
TSP #267 - Power Supply from Hell! Surprising Repair of the Condor SP1016 Arcade Power Supply
17.2K views
October 10, 2025 3:44 PM
In this episode Shahriar takes a look at a 1984 Condor power supply from an old arcade machine. Multiple repair attempts of this supply had failed. Examining the schematics reveals how easily this power supply can self-destruct if the primary NPN switching transistor would fail.
The power supply arrived with a bag of replacement components including the power NPN device. But something doesn’t seem right with the parts. Taking apart the original and replacement transistor tells us everything we need to know…
Please consider supporting The Signal Path:
https://www.TheSignalPath.com/Donate
https://www.Patreon.com/TheSignalPath
Other links:
https://www.TheSignalPath.com
https://www.Twitter.com/TheSignalPath
