Noise Cancelling Headphones

How do Philips noise cancellation headphones work?

Quiet hissing sound when using noise cancellation on my Philips headphones

Will my Philips headphones work if the battery is flat?

I get small electrical static shock from my Philips earphones

How to enable noise cancellation on my Philips headphones?

Is there a way to maintain Philips earphones/headphones?

No sound or distorted sound from my Philips headphones