Capacitors Blog

Round Trimming Potentiometers Features

(Single Turn/ Cermet/ Industrial)
(2 Terminal S tyles)

Round Trimming Potentiometers Electrical Characteristics

Standard Resistance Range 10Ω - 2MΩ
Resistance Tolerance ±30% std
Absolute Minimum Resistance 1% max (≤2K=30Ω)
Contact Resistance Variation 3% max
Resistance Essentially infinite
Adjustment Angle 235° nom

Round Trimming Potentiometers Contact

Fax #: 852 8208 6246
Email : info@suntan.com.hk

A trimmer is a miniature adjustable electrical component. It is meant to be set correctly when installed in some device, and never seen or adjusted by the device's user. Trimmers can be variable resistors (potentiometers) or variable capacitors. They are common in precision circuitry like A/V components, and may need to be adjusted when the equipment is serviced. Unlike other variable controls, trimmers are mounted directly on circuit boards, turned with a small screwdriver and rated for many fewer adjustments over their lifetime. In 1952, Marlan Bourns patented the world's first trimming potentiometer, trademarked "Trimpot".

This capacitor uses thin polyester film as the dielectric.

They are not high tolerance, but they are cheap and handy. Their tolerance is about ±5% to ±10%.

From the left in the photograph
Capacitance: 0.001 µF (printed with 001K)
[the width 5 mm, the height 10 mm, the thickness 2 mm]
Capacitance: 0.1 µF (printed with 104K)
[the width 10 mm, the height 11 mm, the thickness 5mm]
Capacitance: 0.22 µF (printed with .22K)
[the width 13 mm, the height 18 mm, the thickness 7mm]

Care must be taken, because different manufacturers use different methods to denote the capacitance values.

Starting from the left
Capacitance: 0.0047 µF (printed with 472K)
[the width 4mm, the height 6mm, the thickness 2mm]
Capacitance: 0.0068 µF (printed with 682K)
[the width 4mm, the height 6mm, the thickness 2mm]
Capacitance: 0.47 µF (printed with 474K)
[the width 11mm, the height 14mm, the thickness 7mm]

These capacitors have no polarity.

This is a "Super Capacitor," which is quite a wonder.
The capacitance is 0.47 F (470,000 µF).
I have not used this capacitor in an actual circuit.

Care must be taken when using a capacitor with such a large capacitance in power supply circuits, etc. The rectifier in the circuit can be destroyed by a huge rush of current when the capacitor is empty. For a brief moment, the capacitor is more like a short circuit. A protection circuit needs to be set up.

The size is small in spite of capacitance. Physically, the diameter is 21 mm, the height is 11 mm.

Care is necessary, because these devices do have polarity.

In a way, a capacitor is a little like a battery. Although they work in completely different ways, capacitors and batteries both store electrical energy. If you have read How Batteries Work, then you know that a battery has two terminals. Inside the battery, chemical reactions produce electrons on one terminal and absorb electrons on the other terminal. A capacitor is much simpler than a battery, as it can't produce new electrons -- it only stores them.

In this article, we'll learn exactly what a capacitor is, what it does and how it's used in electronics. We'll also look at the history of the capacitor and how several people helped shape its progress.

Inside the capacitor, the terminals connect to two metal plates separated by a non-conducting substance, or dielectric. You can easily make a capacitor from two pieces of aluminum foil and a piece of paper. It won't be a particularly good capacitor in terms of its storage capacity, but it will work.

In theory, the dielectric can be any non-conductive substance. However, for practical applications, specific materials are used that best suit the capacitor's function. Mica, ceramic, cellulose, porcelain, Mylar, Teflon and even air are some of the non-conductive materials used. The dielectric dictates what kind of capacitor it is and for what it is best suited. Depending on the size and type of dielectric, some capacitors are better for high frequency uses, while some are better for high voltage applications. Capacitors can be manufactured to serve any purpose, from the smallest plastic capacitor in your calculator, to an ultra capacitor that can power a commuter bus. NASA uses glass capacitors to help wake up the space shuttle's circuitry and help deploy space probes. Here are some of the various types of capacitors and how they are used.

Air - Often used in radio tuning circuits
Mylar - Most commonly used for timer circuits like clocks, alarms and counters
Glass - Good for high voltage applications
Ceramic - Used for high frequency purposes like antennas, X-ray and MRI machines
Super capacitor - Powers electric and hybrid cars

In the next section, we'll take a closer look at exactly how capacitors work.

Tantalum bead capacitors are polarised and have low voltage ratings like electrolytic capacitors. They are expensive but very small, so they are used where a large capacitance is needed in a small size.

Modern tantalum bead capacitors are printed with their capacitance, voltage and polarity in full. However older ones use a colour-code system which has two stripes (for the two digits) and a spot of colour for the number of zeros to give the value in µF. The standard colour code is used, but for the spot, grey is used to mean × 0.01 and white means × 0.1 so that values of less than 10µF can be shown. A third colour stripe near the leads shows the voltage (yellow 6.3V, black 10V, green 16V, blue 20V, grey 25V, white 30V, pink 35V). The positive (+) lead is to the right when the spot is facing you: 'when the spot is in sight, the positive is to the right'.

For example: blue, grey, black spot means 68µF
For example: blue, grey, white spot means 6.8µF
For example: blue, grey, grey spot means 0.68µF

This is a measure of a capacitor's ability to store charge. A large capacitance means that more charge can be stored. Capacitance is measured in farads, symbol F. However 1F is very large, so prefixes are used to show the smaller values.

Three prefixes (multipliers) are used, µ (micro), n (nano) and p (pico):

µ means 10-6 (millionth), so 1000000µF = 1F
n means 10-9 (thousand-millionth), so 1000nF = 1µF
p means 10-12 (million-millionth), so 1000pF = 1nF

Capacitor values can be very difficult to find because there are many types of capacitor with different labelling systems!

There are many types of capacitor but they can be split into two groups, polarised and unpolarised. Each group has its own circuit symbol.

A capacitor is a passive electronic component that store senergy in the form of an electrostatic field. In its simplest form, a capacitor consists of two conducting plates separated by an insulating material called the dielectric. The capacitance is directly proportional to the surface areas of the plates, andis inversely proportional to the separation between the plates. Capacitance also depends on the dielectric constant of the substance separating the plates.

The standard unit of capacitance is the farad, abbreviate dF. This is a large unit; more common units are the microfarad, abbreviated µF (1 µF =10-6F) and the pico farad, abbreviated pF (1 pF = 10-12 F).

Capacitors can be fabricated onto integrated circuit (IC)chips. They are commonly used in conjunction with transistors in dynamic random access memory (DRAM). The capacitors help maintain the contents of memory. Because of their tiny physical size, these components have low capacitance. They must be recharged thousands of times per second or the DRAM will lose its data.

Large capacitors are used in the power supplies of electro nice quipment of all types, including computers and their peripherals. In these systems, the capacitors smooth out the rectified utility AC, providing pure, battery-like DC.

Aluminum electrolytic capacitor maker Lelon Electronics has seen extra orders from China appliance makers due to the China government's program to promote sales of home appliances in rural areas. The extra orders have covered Lelon's reduced orders from the US and Europe, the company said.

The price of aluminum electrolytic capacitors has been stable since August 2008, while the price of aluminum foil continues to drop, lowering Lelon's cost pressure. However, order visibility for aluminum electrolytic capacitors is still low, the company noted.

Lelon has entered the wind power market with its large-size capacitors, and plans to apply the product to other applications. The company has already shipped a small volume of large-size capacitors to a motorcycle maker and expects to expand into the automotive segment.