Archive for July 22, 2012

Cryogenic Experiments on Passive and Active Electronic Components


In this episode, Shahriar investigates the theory and experimental results of the impact of extreme low temperatures on passive and active components. Liquid Nitrogen in used in a transparent glass Dewar where different components can be fully submerged in the liquid.  Various types of resistors are compared for their temperature stability. An electromagnet which uses Copper coils is used to generate a magnetic field at a constant power consumption at both extreme temperatures. The impact of liquid nitrogen on the junction voltage of an NPN device is measured as well as the frequency shift of a CMOS ring oscillator. Finally, the wavelength shift of an LED submerged in liquid nitrogen is studied. There is a puzzle at the end of this video, please share your thoughts in the comments section. All documents can be downloaded from here.


Teardown and Operation of an Advantest TQ8325 Wavelength Meter


In this episode Shahriar presents the teardown of an Advantest TQ8325 Wavelength Meter. The principle operation of the instrument is explained along with a close up of the free space optics in operation. To verify the functionality of the unit, an infrared laser module is used as a CW coherent source. The impact of the laser diode’s temperature variation on the output wavelength is measured using the wavelength meter.

I’d like to Acknowledge Dr. Jeffery Lee for his consult and expertise on free space optics and fiber optic measurement systems.


Rigol DM3068 6.5 Digit Digital Multimeter Review


In this episode, Shahriar reviews the Rigol DM3068 6.5 Digit Digital Multimeter. The Model DM3068 DMM gives reliable, cost effective, full DMM capabilities measuring DCV, ACV, DCI, ACI, Resistance (2 & 4 Wire), Capacitance, Diode Test, Frequency, and Temperature. These DMMs are designed for simple and efficient bench top use, but include software options for datalogging and remote programming from almost any interface.

Shahriar demonstrates various functionality including a computer guided destructive LED IV tracer to investigate LED failure patterns. The DM3068 can be purchased for $799 US dollars from Rigol Inc. The DM3058 offers similar functionality at 5.5 Digits for $695 US dollars.