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Double Helix & Optical Diffraction Pattern

Introduction In this Post we describe our attempt to replicate the experiment on X-ray diffraction by the DNA molecule. This experimental research, conducted at the time by Rosalind Franklin, allowed us to understand the structure of the DNA molecule. Of course working with X-rays and with “crystallized” DNA molecules is …

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Thyratron based Franck-Hertz Experiment

Introduction With a triode for high currents (known as Thyratron) it is possible to reproduce, albeit in a simplified manner, the famous Franck – Hertz experiment of 1914, which provided one of the first direct tests of the quantized model of atomic energy levels. The experimental apparatus used by Franck …

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PicoAmmeter

Measurement of very small Currents To measure the intensity of an electric current it is necessary to insert an ammeter in series with the circuit, so that the current measured on the ammeter is identical to the current that originally flows in the circuit under examination. Ideally, the ammeter has …

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Geophonic Seismic Traces

Comparison between Geophone and Seismometer The three geophones we used for the construction of the Geophonic Seismometer are very sensitive instruments. Their natural frequency (mechanical resonance frequency) is about 4.5 Hz. At frequencies lower than 1 Hz the response is very attenuated, while it remains fairly constant even at higher …

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Geophonic Seismometer

Geophone In a series of previous posts we have described a horizontal pendulum seismometer: Horizontal Pendulum Seismometer Seismometer : Read-out Electronics Seismometer Traces The one described above is a seismometer with a medium-long period (about 5 sec) suitable for the detection especially of remote earthquakes (telesisms). Neighboring – and weak …

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Seismic Traces

In this post we describe the seismic monitoring activity carried out with the PhysicsOpenLab seismometer. The tool has been described in the posts : Horizontal Pendulum Seismometer, Seismometer : Read-out Electronics. The geographic position of our seismic station has the following data : Latitude : 46° 04′ 01” N (46.067 …

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Seismometer : Read-out Electronics

LVDT Sensor The seismometer position sensor is an LVDT type transducer (inductive displacement transducer). This transducer is an electrical device that allows the measurement of a linear displacement. The transducer is usually made of a tube with three windings arranged with parallel axes and with a mobile ferromagnetic cylindrical core …

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Horizontal Pendulum Seismometer

Introduction The seismometer is a fascinating tool that allows us to “closely” study the geophysics of the earth’s crust. As we know, the earth’s crust is subject to earthquakes which are nothing but vibrations of the rock layers that make up the lithosphere, produced by internal movements that occur underground. …

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Lock-in Amplifier

Introduction A lock-in amplifier (also known as a phase-sensitive detector) is a type of amplifier that can extract a signal with a known carrier from an extremely noisy environment. It is basically an analog multiplier followed by a low pass filter. Practically a lock-in amplifier convert the high frequency signal …

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Faraday Rotation

Introduction The Faraday effect or Faraday rotation is a magneto-optical phenomenon — that is, an interaction between light and a magnetic field in a medium. The Faraday effect causes a rotation of the plane of polarization which is linearly proportional to the component of the magnetic field in the direction of propagation. This effect occurs in most optically transparent dielectric materials …

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