Irish dance (typically the top half of dancers graded after the first two rounds) of dancers are invited back to perform. The Céilí dances used in competitions are more precise versions of those danced in less formal settings. There is a list of 30 Céilí dances which have been standardised and published in An Coimisiún's "Ar Rinncidhe Foirne" as examples of typical Irish folk dances; these are called the "book" dances by competitive stepdancers. Most Irish dancing competitions only ask for a short piece of any given dance, in the interests of time. There are two types of shoes; soft shoes (also
Transformer types impedances between circuits over a limited range of frequencies, using only a length of transmission line. The line may be coaxial cable, waveguide, stripline, or microstrip. Baluns are transformers designed specifically to connect between balanced (non-grounded) and unbalanced (grounded) circuits. These are sometimes made from configurations of transmission line and sometimes bifilar or coaxial cable and are similar to transmission line transformers in construction and operation. Baluns can be designed to not only interface between balanced and unbalanced loads, but to additionally provide impedance matching between those load types. Ferrite-core transformers are widely used in (intermediate frequency) (IF) stages in