Pubblicato da John Doe
There are different types of capacitors. A first basic distinction is between capacitors without polarity and those with polarity. Normally most capacitors with values from 1pF to 820nF are non-polarized and those from 1 μF to 1000μF are polarized. Both have exceptions. Capacitors are usually known to have a tolerance of 5-10% relative to their value. Some electrolytic capacitors have even higher tolerances, such as 20 (for our purpose, the tolerance value is marginal). Here are the basic types of non-polarized capacitors of our interest:
- Disc shaped ceramics;
- Film Polyester Mylar (green);
- Monolithic Ceramic (yellow);
- CBB (red);
All listed capacitors are normally capable of handling voltages such as 25V, 50V, 100V or 200V, so they are perfect for our purposes. Personally I think that the capacitors above 300V are too much for these circuits. And again, a greater tolerance for the tensions makes the bodies always bigger. Then there are values above 1 μF. These are usually electrolytic aluminum or tantalum. The basic electrolytics are cheap, but it is known that they die over time. Those tantalum cost 10 times more, but they are small and last indefinitely. Electrolytics are dimensioned throughout the map for maximum stresses. For our purposes, it is from 16V upwards. I would use any electrolyte that is built for voltages from 25V to 250V. Greater tolerance means large component body. Do not use 10V or lower capacitors in 9V circuits. The operation of the capacitor at a value close to its voltage tolerance reduces its life expectancy even more. Other documentation on the internet says that you should always use double the tolerance - which means that for 18V circuits you should use at least 18V capacitors. Attention: the electrolytic capacitors must be connected to the circuit respecting the polarity represented on the outer envelope. When connected with inverted polarity, electrolytics tend to to blow up.
Almost all capacitors are available in various types of layouts, such as radial and axial.
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