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Crystal radios are the simplest type of radio receiver [2] and can be made with a few inexpensive parts, such as a wire for an antenna, a coil of wire, a capacitor, a crystal detector, and earphones (because a crystal set has insufficient power for a loudspeaker). [3]
With no moving parts and greater power efficiency, these solid-state devices could be operated by small batteries, which revolutionized the process of covert listening. A bug does not have to be a device specifically designed for the purpose of eavesdropping. For instance, with the right equipment, it is possible to remotely activate the ...
A heart rate monitor (HRM) is a personal monitoring device that allows one to measure/display heart rate in real time or record the heart rate for later study. It is largely used to gather heart rate data while performing various types of physical exercise.
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U.S. Army soldiers use a military standard metal detector. A metal detector is an instrument that detects the nearby presence of metal. Metal detectors are useful for finding metal objects on the surface, underground, and under water. A metal detector consists of a control box, an adjustable shaft [dubious – discuss], and a variable-shaped ...
For pipe flows a so-called transit time method is applied where a radiotracer is injected as a pulse into the measured flow. The transit time is defined with the help of radiation detectors placed on the outside of the pipe. The volume flow is obtained by multiplying the measured average fluid flow velocity by the inner pipe cross-section.
Sodium iodide (NaI) containing a small amount of thallium is used as a scintillator for the detection of gamma waves and zinc sulfide (ZnS) is widely used as a detector of alpha particles. Zinc sulfide is the material Rutherford used to perform his scattering experiment. Lithium iodide (LiI) is used in neutron detectors.