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Guest mosul

Pe unde gasesc supercondesatori??

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1.Daca gasestiasa ceva, investeste bani in firma care ii face ... merita ! :x Si eu am cautat cand eram mai mic, si nu am gasit...2.Capacitatea condensatorului se defineste proportional cu :-aria placilor-permitivitatea dielectricului -inversul distantei dintre placi3.Cu multi ani in urma, la o centrala telefonica cineva a vazut un condensator de vreo cateva sute de farazi la 48V , folosit sa tina in spate un consum de ordinul sutelor de amperi pe perioada cat comutau releele alimentarea de la retea la acumulatori ... dar nu era deloc mic , si nu era propriu-zis un condensator...era o chestie cu carbune activ... asta se intampla in perioada dinainte de semiconductori...si centrala mergea pe relee si motorase.4. LA CE ITI TREBUIE ASA CEVA???

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Guest mister_rf

Probabil ca se refera la condensatoarele folosite ca buffer, de 0.22- 2.2F/5V...

Detalii de exemplu aici: http://www.cooperet.com/products_supercapacitors.asp

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Supercap Basics

Capacitors store static electricity by accumulation of charges on two electrodes when a potential is applied. Static accumulation of electricity was first discovered in 1745 at University of Leyde in Holland. Approximately 100 years later, in 1853, Helmholtz discovered the electric double layer where charges accumulated at the interface of the solid electrode and liquid electrolyte. In the 1970's the first double-layer type supercapacitors were developed using high surface-area activated carbon to obtain higher capacitance.

 

The first commercial supercapacitors were high impedance "coin cell" devices, ideally suited for low drain-rate memory, microprocessor and real time clock backup. Wound electrode "cylindrical" supercapacitors, with greater electrode/ current collector surface areas, resulting in lower impedance, were developed next. However ESR did not drop dramatically until the discovery of aerogel carbon and its use as an alternative to activated carbons. Aerogel supercapacitors were first developed at Lawrence Livermore National Laboratory in the 1980's as a power source for small, low-cost space-based missile interceptors called "Brilliant Pebbles." Today, ultra-thin flat designs are also available. Finally, larger supercapacitors are being developed in both cylindrical and prismatic packages with capacitance values ranging from 500F to 3,000F for applications including vehicle traction or starting, and uninterruptible power supplies.

 

A new type of supercapacitor developed by Cooper Electronic Technologies, St. Louis, Mo., achieves significant reductions in ESR over existing capacitors, enabling it to support designs that other devices cannot. The PowerStor Aerogel capacitor, also known as an electrochemical double-layer capacitor (EDLC) or an ultracapacitor, contains electrodes formed from a material called carbon aerogel foam. This foam features high electrical conductivity and controlled ultra-fine pore size, which produces a highly usable surface area for double-layer formation. Low leakage current is said to be another benefit of the new electrode material.

 

This carbon aerogel foam produces lower ESR than other carbon materials used in supercapacitors. For example, the ESR for a 10-F aerogel capacitor measures just 15 mΩ. According to the company, the ESR for competitive parts would be around 200 mΩ.

 

The aerogel capacitor's construction is similar to that of Li-ion batteries and aluminum electrolytic capacitors. A porous separator is placed between two electrodes, creating a sandwich that is wound in "jellyroll" fashion and housed in an aluminum or steel can. The can is then filled with electrolyte and sealed. Leads attached to electrodes protrude from the can (see the figure).

 

Performance, though, is unlike a battery in several respects. The supercapacitor electrostatically stores the charge in the electrochemical double layer formed on the carbon surface of the electrodes. This charge, then, can be released extremely fast. As a result, it can generate specific power up to 4000 W/kg, which may be 10 times greater than a Li-ion battery.

 

In portable applications—where the battery charges up a supercapacitor—such a high power density would allow the use of a smaller battery. The supercapacitor itself is small, with sizes ranging from that of an AA cell to approximately a third of an AAA cell

 

Deci nu faceti afirmatii gratuite... :roll:
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Guest duron750

In terminalele portabile (gen PDA-uri) sunt astfel de condensatori cu capacitati intre 0,33 - 3 F la 5,5 - 12 V, care se folosesc ca baterie de back-up (dar sunt totusi capacitati) Daca gasesti un terminal defect ai putea sa-i folosesti de acolo.

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