This section provides overview, applications, and principles of trimmer capacitors. Also, please take a look at the list of 9 trimmer capacitor manufacturers and their company rankings.
A trimmer capacitor is a variable capacitor used for fine-tuning circuits and adjusting component variations.
The capacitance is adjusted by mechanically turning a knob on the trimmer capacitor with a screwdriver. They are also called semi-fixed capacitors because they are adjusted before use and cannot be shifted once used. Most are for surface mounting and are often chip or round in shape.
Variable capacitors include magnetic variable capacitors and plastic film capacitors, which continuously change their capacitance, in addition to trimmer capacitor.
Trimmer capacitors adjust circuits because their capacitance can be adjusted with a knob.
They are used for a frequency adjustment in oscillation circuits and radio circuits that include quartz crystal units. Specifically, it is a standard component used in the keyless entry for automobiles, automatic ticket gates at train stations, handy radios, power amplifiers, RF modules for Bluetooth, etc. Other uses include radios, clocks, and electronic pens for computers. Nonmagnetic trimmer capacitors are especially used in medical equipment such as MRIs.
The principle of trimmer capacitors are the same as that of an ordinary capacitor: an insulator is placed between two electrodes, which store an electric charge when a voltage is applied. The capacitance can be adjusted by moving one of the electrodes. Air or ceramic is used as the dielectric. Because of their structure, trimmer capacitors cannot be made with large capacitance, so they are small and at the picofarad level.
The following is an explanation of how variable capacitance can be achieved. Like an ordinary capacitor, a dielectric is sandwiched between two metal plates. One plate is fixed, and the other is movable. The plates are often round in shape, and the movable plate can be displaced by rotating it with a knob or the like, using the central axis or the outside of the plate as a guide—the surface area of the displaced plate changes, allowing the capacitance to be varied.
Adjust the capacitance with a screwdriver according to the application at the time of the initial setting. Once adjusted, the capacitance is fixed and used without changing. When adjusting with a screwdriver, be careful not to apply excessive force as it may cause damage.
To adjust the trimmer capacitors, rotate the rotor with a screwdriver to adjust the capacitance to the desired capacitance setting.
There are two types of screwdrivers for adjustment. There are two types of adjustment screwdrivers, manual adjustment screwdrivers and automatic adjustment screwdrivers.
Make sure to place the screwdriver in the groove for the screwdriver and make a preliminary rotation of 360° or more before setting the capacitance.
It is recommended that a load of 1 N or less be used when making adjustments with the screwdriver. Applying a load more significant than this may result in damage or loss of function.
The stray capacitance when adjusting with a screwdriver can be reduced by attaching the terminal to the circuit's ground.
*Including some distributors, etc.
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