em: 4, 5 ou 6 faixas de cor. Digítos Multiplicador Tolerância Coeficiente temperatura Codificação de : 100, 110, 120, 130, 150, 160, 180, 200, 220, 240, 270, 300, 330, 360, 390, 430, 470, 510, 560, 620, 680, 750, 820, 910, ( ) 5% Standard Values Decade multiples are available from 10 through 22 M % Standard Values Decade multiples are available from 10 through 1 M
Dep. Eng. Electrotécnica Nota: O valor obtido vem expresso em Ohm ( ) (*) 3º anel dourado R <10Ω ; 3º anel prateado R <1Ω
Dep. Eng. Electrotécnica
Castanho1 Preto0 Dourado5% 10 x %10 5% 10 x 0,05 = 0,5 9,5 10,5 109,510,5 Tolerância
Dep. Eng. Electrotécnica R330,33 34R234,2 47k47 k 2M12,1 M
Dep. Eng. Electrotécnica 1. Disc Ceramic: While they are limited to quite small values, disc cermaics boast a small and solid construction with comparatively high voltage ratings. They range from 1pF to 0.47µF and are not polarised. This type can often be used to replace a polyester capacitor of the same value. 2. Polyester "Green Caps": Ranging from 0.01µF to 5µF polyester capacitors have similar properties to disc ceramics with some larger values and a slightly larger construction. They are not polarised. 3. MKT Polyester: A varation of polyester capacitors used where price matters less than performance. High temperature stability and accuracy land MKT capacitors in higher end audio circuits and power supplies. They range from 1nF to about 10µF. (values over 1µF are quite expensive) MKTs are not polarised. 4. Tantalum: Tantalum capacitors pack a large capacity into a relatively small and tough package compared to electrolytics, but pay for this in voltage ratings. The device pictured above is 100µF (like the electrolytic next to it) but is rated at 3.6V, compared to 16V. They are often polarised and range from 0.1µF to 100µF. 5. Radial Electrolytic: Used for all values above 0.1µF. Electrolytics have lower accuracy and temperature stability than most other types and are almost always polarised. It's usually best to only use an electrolytic when no other type can be used, or for all values over 100µF. Cheap electrolytics are usually made from plastic and rubber and therefore melt easily during soldering. 6. Axial Electrolytic: The same as other electrolytics but the leads emerge from each end, rather than the same end as in the radial types.
Dep. Eng. Electrotécnica Many products now come under European Directives and to be able to sell them within the EU some must bear the CE mark as a legal requirement. This mark is the manufacturers claim that the product meets all of the relevant European Directives. The VDE Testing Institute as founded in 1920 in Berlin and relocated to Offenbach am Main in 1968 where it has gained worldwide importance. The VDE Testing and Certification Institute is accredited on a national and international level for the testing and certification of electro technical equipment, components and systems. Testing of electro technical products is conducted mainly for safety and electromagnetic compatibility. IEC Symbol 5036ISO 3864, electrical hazard.
Dep. Eng. Electrotécnica tóxico laser Choque eléctrico precaução corrosão radioactividade irritante Inflamável Risco de explosão Sem risco de explosão ionização Modelo europeu ESD
Dep. Eng. Electrotécnica Class 0 – Sem protecção (utilização em locais secos). Um defeito provoca um choque eléctrico. Proíbido em alguns países Class I – Chassis ligado à terra. Um defeito provoca uma fuga para o condutor de terra (normal/ com diferencial) Class II – isolamento duplo – evita necessidade de ligação à terra (não há ligação entre partes eléctricas e as zonas de manipulação) Class III – equipamentos alimentados por SELV (Safety Extra Low Voltage). A tensão de alimentação é reduzida, de forma a que não haja perigo, mesmo com contacto. Classes de isolamento IEC 417 No IEC 417 No. 5019
Dep. Eng. Electrotécnica AWG American Wire Gauge