There are different kinds of trimmer capacitors, but the most common type is made from interleaved layers of metal and Mylar (or some kind of plastic) with a screw that allow the layers to be tightened together, increasing capacitance as needed. Alternate layers of metal are connected to each terminal, basically making a meshed plate capacitor, where the distance between plates is controlled by the screw.
A mica capacitor is simply one that uses the mineral mica as the dielectric or insulator between plates.
Film capacitors cannot be replaced with ceramic or mica capacitors if used for analog signal processing. However, mica capacitors can be replaced with ceramic capacitors in general.
pass AC voltages.
Large value capacitors are difficult to make (large value inductors are even harder to make) and take up large volumes of space. One farad capacitors are available in electrolytics, but are about the size of soup cans. If they were made, kilo & mega farad electrolytic capacitors would have volumes of roughly a thousand & a million soup cans respectively! Nonelectrolytic capacitors would be far larger!!!
Mostly the leakage of capacitors is due to the resistor.
The type of dielectric most often used in variable capacitors is air. Also, trimmer capacitors often use mica.
Nylon
China
It is fair to say that without capacitors (and resistors and inductors) we would have no electronics. Better dielectrics are an area for improvement in capacitors, as is reduction in size.
I have a friend who has the same issue as husband. He uses a small trimmer made by Remington, but their are other brands that you can try.
Trimmer capacitors are used to calibrate (trim) the capacitance in a circuit. They are connected in parallel with some other capacitor, and the circuit is calibrated by observation of response to known stimuli. Since trimmer capacitors are often used in RF circuits, it is generally not possible to make measurement of the capacitors out of circuit because parasitic capacitance at RF is not negligible. Additional question received on April 6th: "I have a 3 terminal trim cap; 2 terminals read continuity, the other not. My question is how do I connect this in a circuit?" In all probability, the two terminals that read continuity are the same terminal, and are simply provided to give three point mechanical stability when soldered into a circuit. You would connect the two terminals that do not have continuity, using either of the terminals that do have continuity, across the capacitor that needed to be "trimmed".
All electrolytic capacitors (e-caps) are polarized capacitors whose anode electrode (+) are made of a special metal on which an insulating oxide layer originates by anodization (forming), which acts as the dielectric of the electrolytic capacitor.
A mica capacitor is simply one that uses the mineral mica as the dielectric or insulator between plates.
Ted Trimmer's birth name is Edmund Charles Kerr-Trimmer.
Nylon trimmer lines are typically made from PA6 (polyamide 6) due to its good balance of strength and flexibility. While PA66 (polyamide 66) can also be used, it is less common for weed trimmer lines due to its higher cost and potential stiffness that may affect performance.
The capacitors those are polarity sensitive are called electrolytic and tantalum capacitors. These capacitors are labeled as positive and negative.
Greenworks mowers are made by a company in China: Changzhou Globe Tools Co., Ltd.