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The key to the development of the transistor was the further understanding of the process of the electron mobility in a semiconductor. It was realized that if there were some way to control the flow of the electrons from the emitter to the collector of this newly discovered diode, an amplifier could be built.
Their low efficiency required a much higher forward voltage to be applied (typically 1.4 to 1.7 V per "cell", with multiple cells stacked so as to increase the peak inverse voltage rating for application in high voltage rectifiers), and required a large heat sink (often an extension of the diode's metal substrate), much larger than the later ...
While standard silicon diodes have a forward voltage drop of about 0.7 V and germanium diodes 0.3 V, Schottky diodes' voltage drop at forward biases of around 1 mA is in the range of 0.15 V to 0.46 V (see the 1N5817 [6] and 1N5711 [7]), which makes them useful in voltage clamping applications and prevention of transistor saturation.
An active-low OR diode logic gate is formed by a keypad containing diodes at each switch, all connected to a shared pull-up resistor. When no switch is closed, the pull-up keeps the output high. But when the switch for any key connects to ground, the output goes low. This OR result can be used as an interrupt signal to indicate that any key has ...
The PIN diode obeys the standard diode equation for low-frequency signals. At higher frequencies, the diode looks like an almost perfect (very linear, even for large signals) resistor. The P-I-N diode has a relatively large stored charge adrift in a thick intrinsic region. At a low-enough frequency, the stored charge can be fully swept and the ...
Shockley derives an equation for the voltage across a p-n junction in a long article published in 1949. [2] Later he gives a corresponding equation for current as a function of voltage under additional assumptions, which is the equation we call the Shockley ideal diode equation. [3]
The characteristic curve (curved line), representing the current I through the diode for any given voltage across the diode V D, is an exponential curve. The load line (diagonal line) , representing the relationship between current and voltage due to Kirchhoff's voltage law applied to the resistor and voltage source, is
Zener diodes have a low breakdown voltage. A standard value for breakdown voltage is for instance 5.6 V. This means that the voltage at the cathode cannot be more than about 5.6 V higher than the voltage at the anode (though there is a slight rise with current), because the diode breaks down, and therefore conducts, if the voltage gets any higher.