10uF Non-Polar (NP) Electrolytic Capacitor

This special type of electrolytic capacitor can be connected either way round in the circuit and is used where the voltage across it may be reversed, as happens about 10% of the time during the flashing cycles in this circuit.  Normal polarised electrolytic capacitors have a definite positive and negative lead.  Circuits that use polarised capacitors where the voltage is the correct way round for most of the time, but periodically gets reversed will work correctly when tested, and will sometimes continue to work for years before failing.  This happens time and again in real TVs and audio equipment.  The small Greek letter mu (μ) is used correctly on the capacitor to denote 10μF (10 microfarads) and uF is more normally used in text, with UF on electronic schematic diagrams. In old books and on ancient capacitors you might see mF used incorrectly.  The voltage rating, in this case 35V is the maximum voltage that the capacitor can withstand before it is damaged and can occasionally burst.  In this circuit running on 6V, a 10V type would do fine.   Non-polar electrolytic capacitors may also be referred to as bipolar types.



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19-DEC-2025: self canonicalised, direct refs