In this episode Shahriar gets a hold of a National InstrumentsVirtualBench! This instrument combines a mixed-signal oscilloscope, function generator, digital multimeter, programmable power supply and digital I/Os in one compact and portable unit. The teardown of the unit reveals a two-board construction with a core single processor which handles all instrument functionality simultaneously.
The unit software (which is embedded inside the instrument memory) is examined in detaile before performing any experiments. Using the VirtualBench, a Si5351 multi-synthesizer clock generator IC is characterized including output signal analyses and I2C decoding. Next by using the function generator and oscilloscope the response of a band-pass 15MHz filter is measured.
In this episode Shahriar takes a detailed look at the new KeithleyDMM7510 7.5-Digit Multimeter. Boasting Keithley’s touchscreen GUI interface, 100mV, 1-Ohm and 10uA ranges makes this multimeter a precision instrument for a variety of applications. The multimeter is also capable of 1MS/s digitization functionality.
The teardown of the unit reveals the complex multi-board construction and analog board design intricacies. After a brief performance verification and GUI overview the multimeter is used in several experiments including measuring the conductivity of a flame, digitizing a large dynamic range multi-tone signal and DC-DC converter noise analysis. Furthermore, the scripting capability of the unit is employed to estimate the location of a short in an Ethernet cable and measure the dielectric constant of a parallel plate capacitor.
In this episode Shahriar examines a faulty R&S FSH3 100kHz – 3.0GHz Portable Spectrum Analyzer. This exceptionally dirty unit does not power on and is missing a power supply and battery. After verifying the correct operation of the battery charger circuit and keypad the problem is traces to a damaged SOT-23-6 MOSFET device which is part of a fly-back DC-DC converter. A replacement MOSFET with a lower current rating proves to be a failure as the device fails on startup. A higher rated MOSFET resolves the problem and device begins to operate correctly.
The block diagram of the system as well as a detailed block diagram of the RF section is presented and correlated with the teardown of the RF section. The super-heterodyne down-conversion circuits and components are examined.
In this episode Shahriar reviews the SiglentSDM3055A 5.5-Digit Multimeter. After a brief look at the instrument’s datasheet, a full teardown is presented. The instrument utilizes a two-board design and a large LCD screen. The SDM3055A provides a comprehensive set of measurements including capacitance as well as various graphing capabilities including histogram, trend and bar graphs. USB and LAN connections are standard and a USB-GPIB can also be purchased. The performance of the instrument is verified through experiments with various functions and setups.
In this episode Shahriar repairs a Stanford Research Systems Model PS350 5000V-25W High Voltage Power Supply. The unit continuously displays 2.5kV without the output being enabled and produces no output voltage. Verification of power supply voltages reveals the issue is linked to a disconnected 15V voltage regulator IC. After the repair, the output voltage is verified with both positive and negative outputs. The principle operation of the instrument as well as the Cockroft-Walton high voltage generator is reviewed.
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.