Suntan - Since the Outbreak of Epidemic

August 25, 2020 Views
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Suntan Technology Company Limited
--All kinds of Capacitors

Dear all of our customers,

Since the outbreak of the epidemic, some countries are got controlled, but some are still fighting against COVID-19.
We sincerely hope that all of you can be safe and healthy, please stay at home and follow the related policies if necessary.

Suntan is working normally, if you have any urgent needs on products, contact us.
Be safe! Be healthy!

Since the Outbreak of Epidemic COVID-19

Suntan New Year New Start

March 1, 2016 Views
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Suntan Technology Company Limited
---All Kinds of Capacitors

The year of the monkey was coming. Wish all customers and friends have a happy and profitable new year.

The monkey in China stands for intelligent, smartness and lively which is deeply loved by most of people.
And also the human's ancestor is the monkey, so human and monkeys have much common in looks and habits.
As the less quantity of the monkey in recent times, monkey has listed in one of the national protected animals.

Back to the point, we currently have following parts in Hongkong warehouse, welcome to order from us at .

Diode Rectifier M7 RoHS


in HK







X2 Met 1uF 275VAC +/-10% P:27.5mm 31.5*13*21.5mm RoHS


in HK







Tan Cap 100uF 16V +/-20% P:2.54 RoHS


in HK






in HK



in HK

Diode LL4148 LL-34 Tape & Reel RoHS


in HK

Su Suntan Variable Capacitors

February 11, 2009 Views
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Suntan Technology Company Limited
---All kinds of Capacitors

Variable capacitors are mostly used in radio tuning circuits and they are sometimes called 'tuning capacitors'. They have very small capacitance values, typically between 100pF and 500pF (100pF = 0.0001µF). The type illustrated usually has trimmers built in (for making small adjustments - see below) as well as the main variable capacitor.

Many variable capacitors have very short spindles which are not suitable for the standard knobs used for variable resistors and rotary switches. It would be wise to check that a suitable knob is available before ordering a variable capacitor.

Variable capacitors are not normally used in timing circuits because their capacitance is too small to be practical and the range of values available is very limited. Instead timing circuits use a fixed capacitor and a variable resistor if it is necessary to vary the time period.

Su Suntan A Bad Capacitor Story Ends Happily

January 31, 2009 Views
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Suntan Technology Company Limited
---All kinds of Capacitors

I worked as a design engineer for an optical-telecom company that had deployed 1000 pieces of equipment worldwide. Having so many modules in the field means a trickle of returns, and it was my job to investigate the failures. One investigation taught me a wonderful lesson.

I received a module whose source of failure was easily identifiable: a charred tantalum capacitor. It failed short, making the whole multithousand-dollar module nonoperational. This surface-mount capacitor—with a 7343 footprint and 20V rating—was sitting on a 12V-dc plane. This failure rate of one capacitor in about 10,000 pieces in this time span was well below the statistical prediction. I took a picture of the fallen capacitor and considered the case closed.

In a few weeks, a customer returned a similar module with a charred and shorted capacitor in the same location. Even including this case, the failure rate was still below statistical prediction. I knew there were five more identical capacitors on the board, sitting in parallel on the same 12V-dc plane. In addition to the module's failure rate, I now had a one-in-six chance with the capacitors. So, I took another picture. I wrote a report to calm upper management, but I had a feeling that I'd better study reliability calculation in general and reliability for tantalum capacitors in particular, and the faster, the better.

In another few weeks, I received another failed module. The same capacitor looked bad. I had by now done my studying and could intimidate other people by saying long and complicated sentences about reliability, but why was it always the same capacitor? Overvoltage? Spikes? No way. The same plane contained plenty of sensitive stuff that would fry well before the capacitor even felt it. Having nothing better, I clung to the theory of excessive ripple current.

The idea of a temperature rise due to ripple current causing the failure gained traction when all three photos of the fallen capacitors revealed a common condition: almost no solder on each negative terminal. The electrical connection was still good, but there was little solder. The capacitor's positive terminal was fine with a fair amount of curvature-profiled solder. I started to promote the idea that the lack of solder had caused impeded thermal contact, but it was only wishful thinking. I calculated the worst ripple current: 10% of the maximum rating. On an operational board, I got less than 5%.

I had already dismissed other ideas—from excessive humidity to airflow turbulence. Suddenly, the picture of the layout popped up in my mind. The layout sections for the five good capacitors were identical: Vias were close to both terminals going down to an internal layer. The bad capacitor had a via at the positive terminal, but, at the negative end, there was a heavy trace going inside the footprint, beneath the capacitor, and only then outside. That's when I knew how to fit together all the pieces of the puzzle.

On the positive terminal, the solder stayed where it was supposed to, clinching the terminal to the PCB (printed-circuit board). On the negative side, however, during assembly, the melted solder drifted under the capacitor and solidified, lifting the negative end and bending the capacitor just enough to create a microcrack—a capacitor's well-known nemesis. I never felt as much excitement writing a technical report as I did the next day.