The most important question of Junction Diode Characteristics in Electronic Devices and Circuits; Explain temperature effects on pn diode characteristics?, is being answered here.
Temperature Effects:
Temperature can have a marked effect on the characteristics of a silicon semiconductor diode as shown in Fig. 1.24. It has been found experimentally that the reverse saturation current Io will just about double in magnitude for every 10°C increase in temperature. |
| Figure 1.24 Variation in diode characteristics with temperature change |
It is not uncommon for a germanium diode with an Io in the order of 1 or 2 A at 25°C to have a leakage current of 100 A _ 0.1 mA at a temperature of 100°C. Typical values of Io for silicon are much lower than that of germanium for similar power and current levels. The result is that even at high temperatures the levels of Io for silicon diodes do not reach the same high levels obtained for germanium—a very important reason that silicon devices enjoy a significantly higher level of development and utilization in design. Fundamentally, the open-circuit equivalent in the reverse bias region is better realized at any temperature with silicon than with germanium. The increasing levels of Io with temperature account for the lower levels of threshold voltage, as shown in Fig. 1.24. Simply increase the level of Io in and not rise in diode current. Of course, the level of TK also will be increase, but the increasing level of Io will overpower the smaller percent change in TK. As the temperature increases the forward characteristics are actually becoming more "ideal" .
No comments:
Post a Comment
Dear visitor, kindly ask us whatever you want related to Electronic Devices and Circuits through comment(s). They will be posted as soon as possible which will be helpful to your development and our improvement. Encourage us by asking and staying connected with us always, thank you. Interested to work for this site (blog), whatsapp @ 7893356131 - NRR.