ABSTRACT
An ideal diode would behave as a short circuit in the forward biased direction and as an open circuit in the reverse biased direction. Manually plotting diode curves can be instructive, but there is an easier way using a function generator and an oscilloscope in X-Y mode. Light emitting diode (LEDs) are very familiar as the glowing indicator lights encountered on the front panels of almost every piece of audio technology. As with all diodes, it is important to differentiate between the anode and the cathode when connecting an LED into a circuit. A silicon diode has a typical forward voltage of 600–700mV, while the Schottky’s forward voltage is usually in the range 150–450mV. Silicon diodes switch from fully off to fully on over a very small voltage range and as such the clipping they introduce can be very harsh. Germanium diodes provide a slightly gentler alternative.
