- The new spring is a flat coil spring with better performance and longer life expectancy.
- These pickups have a large, flat coil with adjustable steel screws as pole pieces, and a pair of flat alnico bar magnets lying under the coil bobbin.
- Wide, flat coil shapes are usually used, to increase coupling . interference to nearby electronics, but they are heavy and bulky so small wireless devices often use air-core coils.
- The wireless device is placed on a flat charger plate ( which can be embedded in table tops at cafes, for example ) and power is transferred from a flat coil in the charger to a similar one in the device.
- Modern radios often use a little ferrite loopstick in the radio, while older ones used a flat coil on the back panel, and older ones still, with less RF amplification, required a long overhead antenna and an Earth ground.