This is a project
of a simple 12V to 9V converter circuit. This DC to DC converter
circuit can be used to convert any 12V DC source to 9V
DC. The circuit can also be used to step down or convert any 12 volt battery
power to 9 volt such as car battery. The heart of the circuit is a LM7809 IC.
LM7809 is a fixed voltage
regulator IC performs DC to DC step down converter tasks in electronic circuits.
The IC has a lot of built in features like thermal shutdown, short circuit
protection and safe operating area protection. LM7809 is a IC of
LM78xx series all the ICs in this series are made for different fixed output
voltages (for example LM7809 IC which is used in this circuit is made for 9 volt
fix output, while LM7805 produces 5 volts). These type of ICs are commonly used in
regulated power supply