I read an electronic magazine in which there is a report on the homemaking for air variable capacitances. After reading, I became interested in air variable capacitances. So I searched some related materials and information about this topic on net, but found that it is not specific at all. Today I would like to discuss my understandings are appropriate.
The project for air variable capacitances begins now:
In some applications, a capacitor is required to provide a variable capacitance value. Variable capacitors are used in such cases. They allow for repeated changes in capacitance by mechanical and electronic means. The air variable capacitor uses air as the dielectric, consisting of two sets of metal pieces, one of which is fixed and the other is rotatable. The metal sheets are arranged in a mesh. The overlapping portions between the two sets of metal sheets can be adjusted by rotating the actuator and the capacitance is changed. But the air gap remains the same.
As the design is simple, powerful, air variable capacitors are widely used. Its most important use is for the radio frequency field, for example, by setting the resonant frequency to tune the radio. They are also important components of RF matching networks, magnetic resonance imaging (MRI) equipment and precision capacitance tables. In addition, they are also used for air and other gas performance tests.
Homemade air variable capacitors
The production of air variable capacitors is very simple. Making air variable capacitors at home requires the following steps:
Design layout for air variable capacitances
1st step, before the hardware step is to design the structural layout and the exact measurement. You can design your layout with Cadvance or any other open source software.
Mark the metal sheet
Place the aluminum sheet on the table and draw a box of 5cmx5cm. Mark the center of the first aluminum sheet and mark it as a reference for every 5cm. Place a compass at the marked hole and draw a circle with an equal diameter on each square aluminum sheet. Then, draw the vertical line with the center point of the arc as the tangent point on the arc of each circle until the end of the aluminum sheet. The number of moving pieces should be one more than the fixed film.
Cut aluminum sheet
After drawing, cut the aluminum sheet. Remove an aluminum sheet and draw a line connecting the center to the left corner. Marks the midpoint of the line between the arc and the left corner. Mark another hole at the corresponding position on the right side corner. For reference, mark all the same holes on all aluminum sheets.
Separate the moving piece from the tablet
Draw a smaller inner ring from the center of each circle and cut the upper half of the inner ring. Drill holes with a diameter of ¼ "to ensure that the aluminum sheet is free from arched, twisted and curled.
Back panel drilling
Take a moving piece and a staircase and place it on the full mesh position on the end plate. The position of the hole in the end plate is marked according to the position of the hole of the two aluminum sheets. Place one of the two end plates over the other and drill holes at the marked hole.
Assembly of aluminum
The next step is to assemble the pieces and pieces. When assembling the moving piece, remove the bolt and remove the bolt head. Place the nut on one end of the bolt and screw it to 5 cm from the end of the bolt. Then insert the first set, two washers, the second set, two washers, and so on until all the inserts are inserted. Finally, insert the stop nut. Repeat the same process and install the patch on the rear panel.
The housing of the capacitor consists of two end plates or covers some of the insulating material. Remove the swivel panel and insert the spindle into the rear panel (to the dicing panel). Place the gasket on the shaft on both sides of the end plate. Turn the shaft to the full mesh position and fasten the other end plates. Use the retaining nut and the gasket to fix it.
Ps: Excuse me if I was wrong in words or expressions as I am a green hand in the field of air variable capacitances. I need continual learnings.
What is your idea ? Do you agree with my ideas ? Any of your ideas would be highly appreciated.