DEPLETION VERSUS ENHANCEMENT

In a JFET, the channel conducts with zero bias, that is, when the potential difference between the gate and the source is zero. As the depletion region grows, charge carriers pass through a narrowed channel. This is known as depletion mode. A MOSFET can work in the depletion mode, too. Metal-oxide-semiconductor technology allows a second mode of operation.
An enhancement-mode MOSFET has a pinched-off channel at zero bias. It is necessary to apply a gate bias voltage E_G to create a channel. If E_G = 0, the drain current I_D is zero when there is no signal input. The schematic symbols for n-channel and p-channel enhancement-mode devices are shown in Fig. 1. In schematic diagrams, they can be differentiated from depletion-mode devices by looking at the vertical lines inside the circles. Depletion-mode MOSFETs have solid vertical lines; enhancement-mode devices have broken vertical lines.

Fig. 1. (a) The symbol for an n-channel enhancementmode MOSFET. (b) The symbol for a p-channel enhancement-mode MOSFET

مواضيع ذات صلة

الحجم النووي Nuclean Size

ربوتات النانو (Nanorobots)

تلسكوبات الأشعة تحت الحمراء والسينية

المقاومة الداخلية المرتفعة لبطارية ليثيوم-ايون

أهمية تقنية النانو (Importance of nanotechnology)

متسعات المرشح على التوالي Filter Capacitors in series

أشباه الموصلات

ظاهرة الحفز الضوئي

مكشاف أشباه الموصلات Semiconductor detector

ميكروسكوبات السليكون

تأثيرات الدفيئة وثقب طبقة الأوزون

مخطط الطاقة لوصلة ال PN