The 7805 is a linear regulator not a dc to dc (switching) converter.Hi! I am trying to make a dc to dc converter using the 78xx series. I have a dc voltage source of 9V. Can I use a 7805 to bring it down to 5V? If yes, what are the other components which I shall require??
That problem likely only occurs if the input voltage is forcibly driven to zero by another load at the input or by a switch to ground.......................
Next, since the input will be open circuited when you turn this off there is a possibility you can reverse voltage this just with the input and output caps. It happens when the input falls faster than the output and too is instantly fatal to the 7805, and is also prevented by a diode from output to input. There should be a schematic of this in every data sheet for the 7805.
If anything else gets connected to the 9V the problem can occur, and things get connected long after the initial circuit with the initial limitations is built. It would be sad for some working circuit to suddenly stop working when some other minor change gets made.That problem likely only occurs if the input voltage is forcibly driven to zero by another load at the input or by a switch to ground.
If the input just goes to an open circuit, such as from a series switch at the 9V output, then the input will simply go to zero at the same rate as the output, and a reverse voltage condition will not occur.
by Aaron Carman
by Duane Benson
by Duane Benson
by Duane Benson