Diode as a circuit element
Where we're headed
- We will define terms like forward bias, reverse bias, and saturation current.
- You will learn some tips for identifying the terminals of a real-world diode.
- We will solve a diode circuit using a graphical method.
Diode - curve
Forward and reverse current
How can I remember the anode and cathode?
Identifying the terminals of a real-life diode
Identify the anode and cathode with a meter
Diode - equation
Detailed look inside the diode - equation
Diode circuit example
If we had used an LED - curve
Addendum: Types of diodes
- Silicon diode - Silicon is the most common material used to make diodes. Silicon has a typical forward voltage of .
- Germanium diode - Made from a different element. Germanium diodes have a lower forward voltage of .
- Schottky diode - Made from a silicon-to-metal contact. The forward voltage is lower than regular silicon diodes, in the range of .
- Zener diode - Intentionally operated in the breakdown region, used as a voltage reference.
- LED (light-emitting diode) - Does what its name says. Otherwise, it acts like a regular silicon diode. LEDs are made by combining materials on either side of Silicon on the periodic table. For example, a yellow LED can be made from gallium arsenide phosphide (GaAsP).
- Photodiode - This diode has a window to let light fall directly on the silicon surface. The current in the diode is proportional to the intensity of light. Solar cells are a form of photodiode.
- Small signal or switching diode - A silicon diode constructed to be very fast going from forward to reverse bias and back. This is done by making the diode physically very small.