Understanding Diodes and Their Problems
Even the simplest active devices harbor the potential for causing baffling troubleshooting problems. Consider the lowly diode. The task of a diode sounds simple: To conduct current when forward biased, and to block current when reverse biased, while allowing negligible leakage. That task sounds easy, but no diode is perfect, and diodes’ imperfections are fascinating. Even these two-terminal devices are quite complex!
All diodes start conducting current exponentially at low levels, nanoamperes and up. An ideal diode may have an exponential characteristic with a slope ΔV/ΔI of:
where mS ...