220V Operated 12V fan | 12V Fan Directly Connecting to 220V AC

This circuit idea is certainly not new, but when it comes to making a trade-of between using a small, short-circuit proof transformer or a capacitive voltage divider (directly from 230 V mains voltage) as the power supply for a fan, it can come in very handy. If forced cooling is an afterthought and the available options are limited then perhaps there is no other choice. At low currents a capacitive divider requires less space than a small, short-circuit proof transformer.

Fan Regulator Circuit | Remote-Controlled Fan Regulator Circuit Diagram

Using this circuit, you can change the speed of the fan from your couch or bed. Infrared receiver module TSOP1738 is used to receive the infrared signal transmitted by remote control. The circuit is powered by regulated 9V. The AC mains is stepped down by transformer X1 to deliver a secondary output of 12V-0-12V. The transformer output is rectified by full-wave rectifier comprising diodes D1 and D2, filtered by capacitor C9 and regulated by 7809 regulator to provide 9V regulated output. Any button on the remote can be used for controlling the speed of the fan. Pulses from the IR receiver module are applied as a trigger signal to timer NE555 (IC1) via LED1 and resistor R4.

5A DC Power Supply | High Power Adjustable DC Power Supply 1.25-25 V with 5A

The main component of the  power supply circuit is LM338K. The circuit 5A power supply with adjustable output voltage from 1.2 to 25V. Circuit is compact, you can see all of the elements except transformer, the printed circuit. Serial element to the cooling body mounted over the aluminum-angular Therefore, lies between the printed circuit boards and regulators LM338K, the other side is mounted on cooling the body with one flat surface.Also you can use a regulator with small fan, I have tested this circuit with computer power supply fan using as a cooling profile with mounting on the heat sink. Its work perfectly when it drive at more than 4.5 A.

10 Amp 13.8 Volt Power Supply Circuit Design