खनन और खनिज उद्योगों में पर्यावरणीय स्थिरता विषय पर विशेषज्ञों का मंथन पर्यावरणीय स्थिरता मानव समाज के निरन्तर अस्तित्व, समृद्धि और स्वास्थ्य के लिए मूलभूत शर्त है। हमारी न्यू जनरेशन को स्पीड और टेक्नोलॉजी पर ध्यान केंद्रित करना होगा ताकि भविष्य को सुनहरा बनाया जा सके। उक्त विचार मुख्य अतिथि श्री एमपी सिंह, प्रधान मुख्य अभियंता, केंद्रीय विद्युत प्राधिकरण विद्युत मंत्रालय भारत सरकार, नई दिल्ली ने व्यक्त किए श्री सिंह भूपाल नोबल्स स्नातकोत्तर महाविद्यालय में भूविज्ञान विभाग द्वारा "खनन और खनिज उद्योगों में पर्यावरणीय स्थिरता" विषय पर आयोजित दो दिवसीय राष्ट्रीय कॉन्फ्रेंस के समापन पर बोल रहे थे। दो दिवसीय राष्ट्रीय कान्फ्रेंस का भव्य समापन सम्मानित अतिथि प्रो विनोद अग्रवाल सदस्य, भारत सरकार नई दिल्ली स्थित MOEFCC की विशेषज्ञ मूल्यांकन समिति, (सि एण्ड टीपी) अपने उद्बोधन में कहा कि पर्यावरण स्थिरता सरकार और समाज दोनों की जिम्मेदारी है। वर्तमान में खनन उद्योग विभिन्न प्रावधानों एवं कानूनों के तहत कार्य कर रहा है ताकि पर्यावरण को सुरक्षित रखा जा सके। आयोजन सचिव डॉ. हेमंत सेन न...
Biasing of pn junction
A p-n junction can be connected to an external battery by two ways.
The method of connecting the p-n junction to an external battery is known as biasing.
There are two types of biasing, forward basing and reverses biasing.
Forward Bias
If p terminal of a p-n junction is connected to positive terminal of an external battery, and n terminal of it is connected to negative terminal of battery then such type of biasing is known as forward bias. It is clear from the figure given below.
In forward bias the current flowing in the circuit is due to majority charge carriers and therefore the resistance is very small and hence the current flowing in the circuit is of the order of milli ampere.
In forward biasing as we increase the potential across the junction, the value of current in the circuit increases very small initially, but after a certain value of potential the depletion region breaks due to high potential across the junction and the value of current increases suddenly.
The value of positive potential or the value of potential in forward bias after which the current increases suddenly is known as knee voltage.
The value of resistance in forward bias is of the order of kilo ohm.
The graphical relation between the forward bias voltage applied to p-n junction diode and the forward current passing through the p-n junction is known as forward characteristic.
The forward characteristic curve of p-n junction along with its circuit diagram is shown in the figure given below
In the central figure the red circles show the electrons and the white circle show the holes. So it is clear from figure that the holes are majority charge carriers in p region, whereas the electrons are majority charge carriers in n region. It means the electrons and holes are minority charge carriers in p and n regions respectively.
Reverse Bias
If p terminal of a p-n junction is connected to negative terminal of an external battery, and n terminal of it is connected to positive terminal of battery then such type of biasing is known as reverse bias. It is clear from the figure given below.
In reverse bias the current flowing in the circuit is due to minority charge carriers and therefore the resistance is very high and hence the current flowing in the circuit is of the order of micro ampere.
In reverse biasing as we increase the potential across the junction, the value of current in the circuit remain almost constant or a very small amount of current increase initially. Since this current is of the order of micro ampere, so we can say there is no current flowing in the circuit initially.
But after a certain value of negative potential, which we applied across the junction, all the covalent bond breaks and the value of current increases abruptly with a very small change of negative potential.
The value of negative potential across the p-n junction or the value of potential applied across the p-n junction in reverse bias after which the value of current increase abruptly is known is breakdown voltage.
The value of resistance in reverse bias is of the order of mega ohm.
The graphical relation between the reverse bias voltage applied to p-n junction diode and the reverse current passing through the p-n junction is known as reverse characteristic.
The reverse characteristic curve of p-n junction along with its circuit diagram is shown in the figure given below
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