Correct. Mica caps without silver do not fail.
Not really a true statement!Yes, mica capacitors, even silver mica capacitors, can fail, although they are generally considered very reliable components due to their stable construction, but factors like aging, manufacturing defects, or extreme environmental conditions can lead to failure. Extreme temperatures or humidity can also affect the performance and lifespan of a mica capacitor. Poor quality mica or improper manufacturing processes can lead to weak or inconsistent capacitors.
Mica capacitors, specifically "silver mica capacitors," are still manufactured today and are used in applications where high stability, low loss, and precise capacitance values are required, particularly in high-frequency circuits like RF transmitters and high-voltage applications due to their excellent electrical properties; however, "clamped mica capacitors" are considered obsolete due to inferior characteristics compared to silver mica capacitors.
These encapsulated silver mica capacitors generally are considered quite reliable. I have bags of these caps at various capacitance and voltage that were manufactured in the 60's and still hold their accuracy and performance today.
__________________________________________________________________________HOWEVER: the open-construction of silver mica capacitors in IF transformers can be very problematic given the right environmental conditions.
