For quartz crystals, an AQL of 0.65% refers to a statistical sampling inspection to accept or reject a production batch, whereas a 100% inspection checks every single relevant component, thereby reducing the risk to the customer to zero. AQL is an industry-standard procedure, but it is not a comprehensive individual inspection. With AQL 0.65%, a defined sample is taken from a delivery batch. Depending on the batch size, inspection level and sampling plan, it is determined how many parts are to be inspected and how many defects are still permissible before the batch is rejected.

This means that even if the sample passes, some parts of the batch remain untested.

For an example batch of 10,000 pieces, under standard assumptions such as normal inspection, General Inspection Level II and a Single Sampling Plan, a sample of 200 pieces may be relevant. If up to 3 defective parts are found in this sample, the entire batch can be accepted; if 4 or more defects are found, it is rejected. This example illustrates the difference between statistical acceptance and actual individual inspection.

PETERMANN-TECHNIK GmbH takes a much stricter approach to all quartz crystals and oscillators, as quality begins with the manufacturing process. The products supplied by PETERMANN-TECHNIK undergo not only statistical sampling but also a comprehensive 100% component inspection. This reduces the risk for the customer to zero and enables them to achieve their 0ppm quality target .

For quartz crystals, SMD crystal oscillators, watch crystals and oscillators , a single faulty component can compromise an entire application. That is why 100% testing is a strong quality argument for reliable, durable and high-performance electronic products.

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