Testing of varactor diodes
Varactor diodes , also known as "capacitance diodes" or "variable reactance diodes" , utilize the property that the junction capacitance of a PN junction changes depending on the applied voltage.
When the reverse voltage is increased, the junction capacitance decreases, while it increases accordingly when the reverse voltage is decreased.
The capacitance of a varactor diode is generally very small, typically ranging from a few pF to several hundred pF . The ratio between maximum and minimum capacitance is approximately 5:1 .
Varactor diodes are primarily used in high-frequency circuits for applications such as automatic tuning, frequency modulation, and modulation. A typical example is their use as variable capacitors in the tuning circuitry of a TV receiver.
Solution details
Measurement requirements:
- Measurement at different frequencies
- Applying a DC bias voltage to analyze the change in capacitance of the varactor diode.
The precise LCR digital bridge TH2840B features an integrated DC bias voltage of ±40 V. This allows the bias voltage to be applied directly to the device under test (DUT) while simultaneously performing a fast and highly precise measurement.
The device meets customer requirements for testing varactor diodes and offers a high-quality solution with an attractive price-performance ratio.