Variable CapacitorsBasic knowledge about variable capacitors

• Why use variable capacitors (VAC)?
• Solution for tight tolerance requirements
• Merits of using VAC
• Examples of application
• Sample requests
• Related Links

Why use variable capacitors (VAC)?

• The variable capacitor absorbs the antenna L value variance for easier f0 adjustment!
• Easier debugging during certification tests.
• Easier variance adjustment when building into cases.

Solution for tight tolerance requirements

Example

A 60 pF variable capacitor can be used in the circuit design to limit the capacitance to 47 pF ±2%.
The above graph shows the capacitance curve of the same variable capacitor.
A capacitance of 47 pF ±2% can be obtained by applying a voltage of 1.3 to 1.45 V.

Merits of using variable capacitors (VAC)

During design:
The resonant frequency deviates from the desired frequency due to the parts tolerance needed to match the antenna tolerance.

Objective:
VAC can be used in the antenna matching circuit to enable adjustment of the resonant frequency.

Examples of application

Sample requests and inquiries

• *We ask that customers please report the evaluation results by around one month after the samples are received.
• *Note that quantities are limited and the free sample offer will end as soon as supplies run out.
• *See the FAQ here for evaluation boards and capacitance measurement methods.

• To request evaluation samples

Related Links

Capacitors FAQ