Because switching power supplies generate EMI, they are subject to FCC and CISPR regulations, both in systems with the power supply installed and in stand-alone applications. Since Class A electronic equipment is marketed for use in a commercial, industrial, or business environment, and Class B electronic equipment is marketed for use in a residential environment, emission limits for Class B equipment, which is likely to be located in close proximity to radio and television receivers, are therefore more restrictive than Class A. In general Class B limits are more restrictive than Class A by a factor of 3 (~10 dB).