National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Speleological flashlight
Kaderka, Jakub ; Šteffan, Pavel (referee) ; Levek, Vladimír (advisor)
Existing speleology headlamps are discussed and several improvement are proposed in the beginning of the thesis. A switched hystersis buck LED driver is designed. Part selection process is mentioned with focus on driver efficiency. Li-Ion charger and battery protection circuit is discussed. Final part of the thesis describes construction of working lamp prototype and measurements of its characteristics. The LED driver reaches efficiency of 96 %, the maximal luminous flux is 869 lumens. The automated light regulation based on measuring amount of reflected light was found to be inefficient in a muddy underground.
Speleological flashlight
Kaderka, Jakub ; Šteffan, Pavel (referee) ; Levek, Vladimír (advisor)
Existing speleology headlamps are discussed and several improvement are proposed in the beginning of the thesis. A switched hystersis buck LED driver is designed. Part selection process is mentioned with focus on driver efficiency. Li-Ion charger and battery protection circuit is discussed. Final part of the thesis describes construction of working lamp prototype and measurements of its characteristics. The LED driver reaches efficiency of 96 %, the maximal luminous flux is 869 lumens. The automated light regulation based on measuring amount of reflected light was found to be inefficient in a muddy underground.

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