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KF5JRV > TECH 12.01.17 13:17l 12 Lines 890 Bytes #999 (0) @ WW
BID : 8689_KF5JRV
Read: GUEST
Subj: Carborundum Crystal
Path: IZ3LSV<IK6ZDE<F1OYP<KQ0I<KA3BVJ<N3IP<NS2B<KF5JRV
Sent: 170112/1215Z 8689@KF5JRV.#NWAR.AR.USA.NA BPQK6.0.13
Carborundum crystal radio circuit
Carborundum detectors were more reliable than the ordinary galena or other types available. The cat's whisker wire was generally of steel to allow more force to be applied to the carborundum. This made the junction less prone to vibration and also some impurities. This often required a different holder to that used for the other types of crystal.
However the junction did need some forward bias to enable it to operate to its best. This was applied by a batteries and the voltage level needed to be adjustable to ensure the best performance.
The use of carborundum in crystal radios tended to be reserved for the more advanced or specialist radios. As they needed batteries to bias the crystal into its operating region, it added additional cost because batteries were not cheap in the early 1920s and 1930s.
73 Scott KF5JRV
KF5JRV.#NWAR.AR.USA.NA
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