In this type of lamp the filament is made of carbon. The melting point of carbon is 3500℃ but its working temperature should not exceed 1800℃ because at high temperature it starts disintegrating and blackens the inside of the bulb. Its temperature Co-efficient is negative. So the resistance decreases at high temperature and taken more current resulting high power consumption. The efficiency of this lamp is low of about 4 lumens per watt. It gives yellowish light. It is generally used for heating purposes and to create a voltage drop for example in battery charging but not for lighting purpose.The approximate life of this lamp is about 800-900 hours.
 Multiple Choice Question (MCQ) of Electronics page-17:241. Which of the following statement is true? a) The saturation voltage VCF of silicon transistor is more than germanium transistor. b) The saturation voltage VCE for germanium transistor is more than silicon transistor. c) The saturation voltage VCE for silicon transistor is same as that for germanium. d) The saturation voltage VCE for silicon transistor is lower than germanium transistor. |
Multiple Choice Question (MCQ) of Electronics page-16:226. Which of the following statement is correct? a) Inner electrons are always present in the semiconductor. b) Bound electrons are always present in the semiconductor. c) Free electrons are always present in the semiconductor. d) Inner and bound electrons are always present in the semiconductor. |
Multiple Choice Question (MCQ) of Electronics page-15:211. The materials whose electrical conductivity is usually less than 1 × 106 mho/m are a) Semiconductors b) Conductors c) Insulators d) Alloys |
Multiple Choice Question (MCQ) of Electronics page-14:196. In which of the following device the base resistors are not added in the package but added externally? a) UJT b) CUJT c) PUT d) None of the above |
Multiple Choice Question (MCQ) of Electronics page-13:181. The conduction in JEFT is always by the a) Majority carriers b) Minority carriers c) Holes d) Electrons e) Holes and electrons simultaneously |