Polystyrene Capacitors
Polystyrene capacitors are capacitors that have a dielectric made up of polystyrene.
They come only in low values, usually 10pF to 47nF.
Normally, their tolerance is 5% to 10% but high precision polystyrene capacitors are also available with tolerances of 1% and 2%.
Working voltages for polystyrene capacitors are 30V to 630V.
They have a high negative temperature coefficient of -125 parts per million per degree Celsius.
Polystyrene capacitors are used in coupling and storage applications due to a high isolation resistance. The precision types are suitable for timing, tuning and filter circuits.
Polystyrene capacitors are constructed like a coil inside, so they are not suitable for high-frequency applications.
A note worth noting is that polystyrene capacitors exhibit a permanent change in value should they ever be exposed to
temperatures much over 70°C; they do not return to their old value upon cooling.
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