A diode is a semiconductor device that allows current to flow primarily in one direction. It has two terminals: the anode (positive) and the cathode (negative). For a diode to be forward biased, the anode must be connected to a higher potential (positive terminal of the battery) and the cathode to a lower potential (negative terminal of the battery). This reduces the barrier potential, allowing current to flow easily.

In the given options, the correct forward-biased connection is the one where:

• The anode (p-side) is connected to the positive terminal of the battery.
• The cathode (n-side) is connected to the negative terminal of the battery.

Looking at the images, the correct diagram is the second one (from the top), where the p-side (anode) is connected to the positive terminal and the n-side (cathode) to the negative terminal. This setup ensures the diode is forward biased.

Key characteristics of a forward-biased diode:

• It conducts current.
• The voltage drop across it is approximately 0.7 V for silicon diodes and 0.3 V for germanium diodes.
• It behaves like a closed switch in ideal conditions.

Related Topics

PN Junction Diode: A diode is formed by joining p-type and n-type semiconductors. It has a depletion region and exhibits rectifying properties.

Semiconductors: Materials like silicon and germanium with conductivity between conductors and insulators. Doping creates p-type and n-type semiconductors.

Formulae

The current-voltage relationship for a diode is given by the Shockley diode equation:

where $I$ is the diode current, $I_s$ is the reverse saturation current, $q$ is the electron charge, $V$ is the voltage across the diode, $\eta$ is the ideality factor, $k$ is Boltzmann's constant, and $T$ is the temperature in Kelvin.