A diode has a definite polarity: it has a positive terminal called the anode and a negative terminal called the cathode.
Understanding Diode Polarity
The polarity of a diode is crucial for its function as a one-way valve for electrical current. Current can only flow easily from the anode (positive) to the cathode (negative) in what's called forward bias. When the diode is reverse biased (cathode more positive than the anode), it blocks current flow.
Diode Terminals:
- Anode: The positive terminal of the diode.
- Cathode: The negative terminal of the diode. Diodes typically have a band or marking on the cathode end to easily identify polarity.
Polarity and Current Flow
| Bias | Anode Voltage Relative to Cathode | Current Flow |
|---|---|---|
| Forward Bias | Higher | Current flows easily from anode to cathode. The diode is "on." |
| Reverse Bias | Lower | Very little current flows (ideally none). The diode is "off." |
Incorrectly connecting a diode with the wrong polarity will prevent the circuit from working as intended and can potentially damage the diode or other components. Therefore, identifying the anode and cathode is essential when using diodes in electronic circuits.
