A crystal detector includes a crystal, a special thin wire that contacts the crystal, and the stand that holds those components in place.
12.
Instead of a crystal detector, a Fleming valve ( tube diode ) could be used; it was a stable detector, but not very sensitive.
13.
Adding to their problems was the lack of a suitable rugged crystal detector, which was the only system able to reliably detect these high frequency signals.
14.
The most popular crystal detector consisted of a small piece of galena crystal probed by a fine wire commonly referred to as a " cat's-whisker detector ".
15.
The energy of the photon, 159 keV, is ideal for the NaI ( sodium iodide ) crystal detector of current gamma cameras and also for the pinhole collimators.
16.
The earliest crystal receivers did not have a tuned circuit at all, and just consisted of a crystal detector connected between the antenna and ground, with an earphone across it.
17.
When the station opened in 1912 it used a quenched spark-gap transmitter manufactured by Telefunken, and a receiver with a locally built crystal detector ( using galena from Northampton ).
18.
To improve the sensitivity of some of the early crystal detectors, such as silicon carbide, a small forward bias voltage was applied across the detector by a battery and potentiometer.
19.
Nevertheless, the expense of the early vacuum tubes and the batteries needed to run them meant that the crystal detector remained in commercial and military use for almost a decade more.
20.
The detection device that did this was called a AM radio transmission was developed to transmit sound, around World War I, crystal detectors proved able to receive this transmission as well.
