how much power is delivered to the fan and therefore how fast it spins. Older such controls employed a choke— a large iron-cored coil— as their regulator; these controls were typically large, boxy, and surface-mounted on the wall. They had anywhere from four to eight speeds. Newer versions of this type of control do not use a choke as such, but much smaller capacitors and/or solid-state circuitry; the switch is typically mounted in a standard in-wall gang box. The old one is called electrical fan regulator that works on the principle of reducing voltage and the new one is called electronic fan regulator that works on the principle of switching that control the time duration of the power supply. The new electronic fan regulator is more power efficient. Digital wall control. With this style of control, all of the fan's functions— on/off status, speed, the direction of rotation, and any attached light fixtures— are controlled by a computerized wall control, which typically does not require any special wiring. Instead, it uses the normal house wiring to send coded electrical pulses to the fan, which decodes and acts on them using a built-in set of electronics. This style of control typically has anywhere from three to seven speeds. Wireless remote control. In recent years, remote controls have dropped in price to become cost-effective for controlling ceiling fans. They may be supplied with fans or fitted to an existing fan. The hand-held remote transmits radio frequency or infrared control signals to a receiver unit installed in the fan. However, these may not be ideal for commercial installations as the controllers require batteries. They can also get misplaced, especially in installs with many fans. Directional Switch. Most ceiling fans typically feature a small slide switch on the motor body of the fan itself, which controls the direction in which the fan rotates. In one position, the fan is caused to rotate clockwise, in the other position the fan is caused to rotate counter-clockwise. Given that the fan blades are typically slanted, this results in the air either being drawn upwards or brought downwards. While the user can select which they prefer, typically air is blown downwards in summer and lifted upwards in winter. The downwards blowing is experienced as "cooling" in summer, while the upwards convection brings ceiling-hugging warm air back down throughout the room in winter. Classifications Ceiling fans can be classified