What is a varactor diode, its composition, classification, operating procedures, and development trends 2

3. Principle:

The capacitance value of a varactor diode is achieved by adjusting the space charge region at the junction interface. When a reverse bias is applied to the diode, the space charge region expands, resulting in an increase in capacitance value; When a forward bias is applied, the space charge region shrinks, resulting in a decrease in capacitance value. The variability of this capacitor is controlled by the electric field between PN junctions.

4. Classification:

Varactor diodes can be classified into various types based on the material type and structural characteristics between PN junctions, such as varactor diodes, complementary pair (COP) diodes, MESFET diodes, etc.

5. Operating procedures:

When operating a varactor diode, the following points should be noted:

(1) Reasonable bias voltage: Select the appropriate bias voltage according to specific application requirements to ensure the required capacitance range.

(2) Protection against reverse current: To prevent diode burnout, attention should be paid to limiting the magnitude of reverse current and avoiding exceeding its rated value.

(3) Temperature control: The capacitance value of the varactor diode will fluctuate with temperature changes. To achieve better performance, the ambient temperature should be controlled as much as possible.