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8 Apr 2014

In this episode Shahriar repairs an Agilent 86120B Multi-Wavelength Meter. The instrument reports “E14 Data Acquisition Problem” which corresponds to a potential internal HeNe reference laser failure. After the instrument disassembly, the old HeNe laser is removed and its optical power is compared to that of a new laser. The measurements confirm that the old laser has significantly deteriorated in output light intensity. The new laser is fitted inside the unit and the error message is eliminated. The free-space optic portion of the instrument is revealed and the principle operation is reviewed. Various components of the Michelson Interferometer is examined.

To test the correct operation of the instrument, a single tone semiconductor laser is applied to the unit and the result is compared to a different wavelength meter. The concept behind the operation of a Fabry-Perot laser is also presented before the signal is applied to the wavelength meter.

Teardown, Repair and Experiments of an Agilent 86120B Multi-Wavelength Meter - [Link]

7 Apr 2014

This GU10 LED spot light is cheap (£3 including postage) and bright. But it’s also lethal! There’s a 50% chance of putting live mains within a few microns of the metal casing (which is what you’ll be holding when you insert it) and there’s no earth to protect you. It’s like playing Russian Roulette with 240v AC mains. This sort of thing gives new technology a bad name. Avoid it if you want to stay alive.

Dangerous GU10 LED Spot Light is Cheap and Bright but could Kill You – Seriously - [Link]

6 Apr 2014

This video reviews the two most common reasons why the output amplitude setting on a function or signal generator doesn’t match what is read on an oscilloscope. This can be due to an incorrect attenuation setting on the scope, but is most commonly due to the fact that the generator is not presented with the load impedance that it is expecting. To correct this most common case, you can either use the correct load impedance, or tell the generator what load you are presenting it with.

Why your Function Generator’s output voltage reading can be wrong - [Link]


6 Apr 2014

In this tutorial Dave explains what Operational Amplifiers (OpAmps) are and how they work. The concepts of negative feedback, open loop gain, virtual grounds and opamp action. The comparator, the buffer, the inverting and non-inverting amplifiers, the differential amplifier, and the integrator circuit configurations are also explained. Then a practical breadboard circuit to demonstrate a virtual ground and the effect of voltage rail limitations.

EEVblog #600 – OpAmps Explained - [Link]

4 Apr 2014

Dave comments on the Sparkfun/Fluke multimeter customs trademark/trade dress fiasco, and shows off the new low cost Fluke 114/117 Kit Multimeter about to be released.

EEVblog #597 – Fluke 114 Kit Multimeter + Sparkfun/Fluke Rant - [Link]

4 Apr 2014

Julian Ilett writes:

I discovered that due to a lucky co-incidence of voltage and internal resistance, a 100W LED can be connected directly across the terminals of two 18V Nickel Cadmium power tool batteries. And that means you can build a 100 Watt (7,500 Lumens) flashlight for less than $10 (not including batteries).

Monster 7,500 Lumens 100W LED Flashlight for under $10 - [Link]

30 Mar 2014

This video discusses how to measure the ESR (equivalent series resistance) of a capacitor using an oscilloscope and function generator. All of the capacitors tested in this video were 220uF electrolytic caps. In reality, the resistance in the plates of a dried out electrolytic capacitor can’t be modeled as a simple series resistor, but for the purposes of identifying good from bad, this simplification works fine.

Measure Capacitor ESR with an Oscilloscope and Function Generator - [Link]

30 Mar 2014

Dave takes a look at the world’s cheapest temperature controlled soldering station, the $16 Hakko 936 knockoff Yihua 936 from Hobby King. How does it compare to the older genuine Hakko 926? Also, thermal capacity comparison testing is done on those two irons plus the high thermal capacity JBC. Sagan also gives his verdict.

EEVblog #596 – World’s Cheapest Soldering Station – Yihua 936 - [Link]

22 Mar 2014

In this episode Shahriar reviews and demos the second revision of the industry’s first Mixed Domain Oscilloscope from Tektronix. The MDO4000B series offers improved signal integrity and performance. The reviewed model is a MDO4104B-6 which offers 16-Channel Logic Analyzer, 4-Channel Oscilloscope with 1GHz of analog bandwidth as well a 6GHz Spectrum Analyzer with greater than 1GHz of instantaneous capture bandwidth with 65dB of dynamic range.

After an overview of the instrument’s interfaces and built quality, the block diagram and principle operation of the instrument is explained. The time-correlated digital, analog and RF capturing capability is described and its advantages for debugging complex mixed-domain systems is explored. Instrument probes, accessories and various modules are also presented.

Tektronix MDO4104B-6 Mixed Domain Oscilloscope (MDO4000B) Review and Experiments - [Link]

5 Mar 2014

A crazy way to convert a 600mil DIP to 300mil. [LPC1114] - [Link]





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