European mains electricity. On the output coils, taps are used to provide a range of output potentials. Prototyping transformers are often supplied in cases which have spring-loaded contact taps - one common and several taps (for example, Common; 3 V; 5 V; 10 V.) Inductors Coil taps on inductors are quite rare, but are sometimes used for band switching in tuning circuits. Coil Pickups Coil pickups used with measuring instruments often feature coil taps to compensate for band rejection or equipment input impedance. Telephone tapping Coil taps can be used as a rudimentary method for recording telephone conversations. See Telephone tapping. References Electromagnetic components