DC Fan Using 9 Volts Battery: In this project shows how to make DC Fan Using with 9V Battery, and its suitable for schools projects like Mini Fan concepts on how to rotate fan by utilizing battery power and why does rotate fan these type of questions can be solved from this project subjected to kids.  Components Required for 9 Volts DC Fan: 1. Small DC motor 2. 9 Volts Battery 3. Fan 4. ON and Off Switch 5. Battery Connector How To Make Homemade DC Fan Using 9V Battery Making Video:

How to make a Power Supply For Adjustable Voltage And Current, The circuit diagram of the power supply is shown in Fig. 1. It is built around bridge rectifier (BR1), adjustable voltage regulator LM350 (IC1), transistors BC327(T1) and BC337(T2), and a few other components. Fig. 1: Circuit diagram of the simple power supply with adjustable voltage and current with LM350 Input to connector CON1 can be AC or DC. If you use an 18 to 20Vrms transformer with 2A current ratings, you can have output voltage VOUT1 from 1.2V up to around 16.5V available at CON3, and VOUT2 from 0V to 15V available at CON2. Input is protected with 2A fuse F1. Capacitors C3 and C5 (2200µF) are the main filtering capacitors. Input voltage is limited by maximum input voltage of IC LM350. Maximum power dissipation of LM350 is around 25W. According to the data sheet, input voltage of LM350 can be from around 4.5V to 35V, and output voltage can be adjusted from 1.2V to 33V; however, we need output voltage lower than 17V....