In this episode Shahriar repairs and analyzes two instruments. An HP 5245L Electronic Counter which uses 1960’s technology to achieve some incredible performance. The HP unit uses eight beautiful nixie tubes as its main numeric display. The instrument requires repair, calibration and some upgrades to prepare it for use as a nixie tube clock! The source of the clock is an ERA Instruments EasySynth++ which is a high performance, open-source synthesizer up to 20GHz:
https://erainstruments.com/
The architecture and teardown of the EasySynth++ is also presented. The two instruments are combined with some custom scripts to create the world’s (?) most complicated nixie tube clock.
In this episode Shahriar investigates the mysteries of a W-Band fundamental LO balanced mixer module based on GaAs Schottky Barrier Diodes. The mixer offers a very high IF bandwidth of 35GHz and LO driver requirements of 13dBm between 75-110GHz.
The teardown reveals the waveguide to coaxial transitions as well as the interface to the pair of Schottky diodes. High resolution microscope analysis provides a detailed view of the precise machined waveguide ports.
This instrument offer four-quadrant operation, 60W total output power, 6.5 digit resolution as well as 500kS/s digitizers on both voltage and current readbacks. The instrument also offers a verity of output control and arbitrary waveform generation. This review is organized as follows:
00:00 – Introductions
00:50 – Front & back panels, interfaces, design
02:40 – Detailed teardown & architectural analysis
08:36 – Pooch!
08:45 – USB Power Bank experiment, NGU GUI design, primary capabilities
13:20 – Multi-quadrant operation, sink/source conditions
15:49 – High-speed sampling, auto-ranging and transient detection
18:29 – Deep-sleep battery drain detection of Fluke 233, graphical viewer, fast logging
22:35 – Characterizing a DC/DC converter, transient output current
27:19 – High output capacitance mode, oscillation detection
29:45 – Current/voltage priority modes
30:40 – Fast arbitrary waveform generation,
34:20 – Additional functions, OVP, OCP, OPP, Modulation Input, trigger IOs, slew control, fast transient
36:18 – Concluding remarks
In this episode Shahriar takes a look at an unusual vintage HP instrument from the 1950s. The unit has a vacuum-tube-like core with a pair of banana plug interface.
After restoration, the instrument principle of operation, teardown and schematics are presented. Several experiments demonstrate the use-case as well as the correct operation of the unit.
In this episode Shahriar takes a look at a pair of COVID-19 electronic home kits. These Bluetooth enables devices are manufactured by ellume. Both of these tests had produced false-positive results. The optical readout mechanism of the devices are examined as well as the general design of the unit.
This video is not about which COVID-19 home test kit you should purchase. This is an exploration and analysis of this particular device for educational purposes only. For all medical advice regarding COVID-19, please contact your doctor.
The Signal Path (TSP) is an electrical engineering video blog for industry professionals, students and hobbyists. TSP is a non-for-profit website dedicated to provide free education spanning a wide range of electrical engineering topics. Equipment reviews, tutorials and repair videos are posted regularly.
