Proximity effect means the interaction of magnetic fields associated with adjacent current carrying conductors parallel to each other causing a further redistribution of the current which likewise increases the ohmic d.c. the resistance of the conductor. Proximity effect increases with the conductor diameter and becomes maximum when the cables are practically in contact. Therefore, a correction is mainly necessary for L.T. cables of large cross section. Again this effect can also become important under the certain condition of cable installation. When cables are laid parallel to metal beams, walls etc as frequently happens in buildings or ships this effect increases the apparent impedance of these cables appreciably. Ultimately proximity effect exerts influence on the current carrying capacity of the cables.
A horizontal spacing is desirable in order to reduce the effect of mutual heating. In case they close or touch one another the effect of mutual heating increases and accordingly, the current carrying capacity of cable decreases sufficiently.
 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 |