English pewter 16th century a third grade was added. The first type, known as "fine metal", was used for tableware. It consisted of tin with as much copper as it could absorb, which is about 1%. The second type, known as "trifling metal" or "trifle", was used for holloware. It is made up of fine metal with approximately 4% lead. The last type of pewter, known as "lay" or "ley" metal, was used for items that were not in contact with food or drink. It consisted of tin with 15% lead. These three alloys were used, with little variation, until the 20th
Distributed element filter composite structures can implement any of the filter families (Butterworth, Chebyshev, etc.) by approximating the rational transfer function of the corresponding lumped element filter. This correspondence is not exact since distributed element circuits cannot be rational and is the root reason for the divergence of lumped element and distributed element behaviour. Impedance transformers are also used in hybrid mixtures of lumped and distributed element filters (the so-called semi-lumped structures). Another very common component of distributed element filters is the stub. Over a narrow range of frequencies, a stub can be used as a capacitor or an inductor (its impedance is