Saturday, May 27, 2017

Measuring capacitance of variable capacitor (varicap)

This is just a short post of measuring the capacitance of the variable capacitor at maximum capacitance.. 

The first picture is the measurement taken at both the stators ( stationary plates), this is used for magnetic loop as per the diagram below.

Capacitance at both stators

Position of variable capacitor

The below picture measure the capacitance between the stator (stationary plates) rotor ( moving plates).

Wednesday, May 3, 2017

Variable Capacitor for ham radio

A short posting with pictures of variable capacitors made using a CNC machine by 9W2CEW. The CNC cut both the rotor (moving plates) and stator (stationary plates) in one go. Refer to the last picture below.

This design is usually found in loop antenna to change the capacitance value from the shaft.

Side view

Variable caps with laser cut cover

0.7 mm aluminium plates