Modern engine designs have done away with the distributor and coil, instead performing the distribution function in the primary circuit electronically and applying the primary (low-voltage) pulse to individual coils for each spark plug. In some cars, the coils are mounted together in a 'coil pack'; others utilize a coil located very near to or directly on top of each spark plug (Direct Ignition or coil-on-plug). This avoids the need to switch very high voltages, which is very often a source of trouble, especially in damp conditions. These systems also allow finer levels of ignition control by the engine computer, which assists in increasing power output, decreasing fuel consumption and emissions, and implementing features such as Active Fuel Management.