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  • EEVblog #605 – Fig.8 & Cardioid Microphone Patterns

    Posted on April 20th, 2014 EEVblog 6 comments

    Doug Ford, former head designer from Rode Microphones continues with Part 2 of the microphone technology series by explaining the construction of noise cancelling Figure 8, cardioid, and hyper cardioid microphones. Also, how the polar patterns and responses relate to the physical construction, and how the frequency response is affected.
    Proximity boost effect,
    Microphone calibration is also discussed using a home made artificial voice speaker box.
    And practical considerations about foldback wedges used in stage performances and how to avoid feedback using proper microphone technique.
    And did Jimmy Barnes offer Doug a swig from his bottle of Vodka?
    Forum HERE

  • EEVblog #604 – Sinclair C5 Restoration – Part 1

    Posted on April 17th, 2014 EEVblog 18 comments

    The obligatory “before” video showing Dave’s Sinclair C5 electric “car” and its poor condition before commencing restoration work.

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

    Posted on April 16th, 2014 EEVblog 8 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.
    Forum HERE

  • EEVblog #602 – Introduction to Microphones

    Posted on April 12th, 2014 EEVblog 11 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