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  • EEVblog #603 – Gas Sensor Teardown – Dräger Multiwarn II

    Posted on April 16th, 2014 EEVblog No comments


    What’s inside a Dräger Multiwarn II gas detection warning system used in mining, oil, chemical, and emergency services etc to detect hazardous or explosive atmospheres.
    Intrinsic safety design and how both catalytic bead and infrared IR gas detectors work, and pellistors.
    And a teardown of a Hydrogen Sulfide (H2S) sensor.

    http://www.a11supply.com/images/file/rev1_MultiWarn%20II_En.pdf
    http://www.draeger.com/sites/assets/PublishingImages/Products/cin_x-am_5600/US/draeger-sensor-portable-handbook-9046571.pdf
    http://www.xinpian.net/MOTOROLA/MC68HC711/MC68HC11E1.pdf
    Forum HERE

  • EEVblog #602 – Introduction to Microphones

    Posted on April 12th, 2014 EEVblog 6 comments


    In the first of a series of videos tutorials on microphones, Doug Ford, former head designer at Rode Microphones explains the basics of how microphones work, the different types – carbon, dynamic, ribbon, condensor/electret, and how the omnidirectional pattern works.
    Also, the internal construction of a high end measurement microphone.

    Discuss on the Forum HERE

  • EEVblog #601 – Why Digital Oscilloscopes Appear Noisy

    Posted on April 10th, 2014 EEVblog 11 comments


    Why do digital oscilloscopes appear noisier than traditional analog oscilloscopes?
    Dave busts the myth that digital scopes are noiser than analog scopes, and demonstrates what inherent advantages digital scopes can have over analog scopes in terms of true waveform capture. And also why your analog scope may be hiding important signal detail from you.
    Demonstrations of how memory depth, analog bandwidth, averaging, and intensity graded displays can all effect the signal detail you see on your digital oscilloscope.
    And how long exposure camera shots on analog oscilloscopes can reveal detail you can’t see with your eyes.

    Demonstrations are done on the new Tektronix MDO3000, the Rigol DS1052E, the Tektronix TDS220, and Tektronix 2225 analog oscilloscope.
    Previous video on common mode noise measurement
    Forum HERE

  • EEVblog #600 – Opamps Explained

    Posted on April 6th, 2014 EEVblog 32 comments


    The most often requested video! 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.
    All EEVblog Opamp related videos are HERE

    Forum HERE

  • EEVblog #599 – 5 years of the EEVblog

    Posted on April 4th, 2014 EEVblog 38 comments


    The EEVblog is 5 years old today!
    Just a quick thanks to everyone who has supported me and the blog.