Capacitor and trimming potentiometer make Suntan Technology high revenue
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---All kinds of Capacitors
SMD Trimmer Potentiometer Features
SMD Trimmer Potentiometer Electrical Characteristics
SMD Trimmer Potentiometer Pictures
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---All kinds of Capacitors
Phenolic Trimming Potentiometers Features
Phenolic Trimming Potentiometers Electrical Characteristics
Phenolic Trimming Potentiometers Pictures
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---All kinds of Capacitors
Circularity Trimming Potentiometer Features
Circularity Trimming Potentiometers Electrical Characteristics
Circularity Trimming Potentiometer Pictures
7 Terminal Square Trimming Potentiometers - Electrical Characteristics | |
---|---|
Standard Resistance Range | 10Ω - 2MΩ |
Resistance Tolerance | ±5%, ±10% |
Absolute Minimum Resistance | ≤1% R or 2Ω |
Contact Resistance Variation | CRV≤1%or 2Ω |
Insulation Resistance | R1≥1GΩ(500Vac) |
Withstand Voltage | 707Vac |
Effective Travel | 250° |
In these devices, polystyrene film is used as the dielectric. This type of capacitor is not for use in high frequency circuits, because they are constructed like a coil inside. They are used well in filter circuits or timing circuits which run at several hundred KHz or less.
The component shown on the left has a red color due to the copper leaf used for the electrode. The silver color is due to the use of aluminum foil as the electrode.
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---All kinds of Capacitors
The multilayer ceramic capacitor has a many-layered dielectric. These capacitors are small in size, and have good temperature and frequency characteristics.
Ceramic capacitors are constructed with materials such as titanium acid barium used as the dielectric. Internally, these capacitors are not constructed as a coil, so they can be used in high frequency applications. Typically, they are used in circuits which bypass high frequency signals to ground.
These capacitors have the shape of a disk. Their capacitance is comparatively small.
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---All kinds of Capacitors
A capacitor's storage potential, or capacitance, is measured in units called farads. A 1-farad capacitor can store one coulomb (coo-lomb) of charge at 1 volt. A coulomb is 6.25e18 (6.25 * 10^18, or 6.25 billion billion) electrons. One amp represents a rate of electron flow of 1 coulomb of electrons per second, so a 1-farad capacitor can hold 1 amp-second of electrons at 1 volt.
A 1-farad capacitor would typically be pretty big. It might be as big as a can of tuna or a 1-liter soda bottle, depending on the voltage it can handle. For this reason, capacitors are typically measured in microfarads (millionths of a farad).
To get some perspective on how big a farad is, think about this:
If it takes something the size of a can of tuna to hold a farad, then 10,080 farads is going to take up a LOT more space than a single AA battery! Obviously, it's impractical to use capacitors to store any significant amount of power unless you do it at a high voltage.
Applications
The difference between a capacitor and a battery is that a capacitor can dump its entire charge in a tiny fraction of a second, where a battery would take minutes to completely discharge. That's why the electronic flash on a camera uses a capacitor -- the battery charges up the flash's capacitor over several seconds, and then the capacitor dumps the full charge into the flash tube almost instantly. This can make a large, charged capacitor extremely dangerous -- flash units and TVs have warnings about opening them up for this reason. They contain big capacitors that can, potentially, kill you with the charge they contain.
Capacitors are used in several different ways in electronic circuits:
In the next section, we'll look at the history of the capacitor and how some of the most brilliant minds contributed to its progress.
In an electronic circuit, a capacitor is shown like this:
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When you connect a capacitor to a battery, here's what happens:
Once it's charged, the capacitor has the same voltage as the battery (1.5 volts on the battery means 1.5 volts on the capacitor). For a small capacitor, the capacity is small. But large capacitors can hold quite a bit of charge. You can find capacitors as big as soda cans that hold enough charge to light a flashlight bulb for a minute or more.
Even nature shows the capacitor at work in the form of lightning. One plate is the cloud, the other plate is the ground and the lightning is the charge releasing between these two "plates." Obviously, in a capacitor that large, you can hold a huge amount of charge!
Let's say you hook up a capacitor like this:
Here you have a battery, a light bulb and a capacitor. If the capacitor is pretty big, what you will notice is that, when you connect the battery, the light bulb will light up as current flows from the battery to the capacitor to charge it up. The bulb will get progressively dimmer and finally go out once the capacitor reaches its capacity. If you then remove the battery and replace it with a wire, current will flow from one plate of the capacitor to the other. The bulb will light initially and then dim as the capacitor discharges, until it is completely out.
In the next section, we'll learn more about capacitance and take a detailed look at the different ways that capacitors are used.