For school, I need to design a circuit that can provide power at appropriate current and voltage to charging devices (and also incorporate an LCD and Arduino board). I am studying mechanical engineering but hey, first year and I am absolutely terrible with electrical.
I have a DC power supply of 12W: 5V & 2.4A. I need to drop the voltage by approximately 0.65V to 4.35V to charge a 4.2V device. I was planning use a resistor and then a switch that would add another resistor when desired to achieve a further drop to 3.7V. I am unclear on how to control voltage and current at the same time.
I was thinking for the first voltage drop that a resistor of 0.27Ω would cause a drop of 0.65V. Vdrop = 2.4A * R = 0.65V so R = 0.65V/2.4A.
I'm not really sure where to go from here or if this is wildly wrong. Any help would be appreciated.
Thanks,
James
I have a DC power supply of 12W: 5V & 2.4A. I need to drop the voltage by approximately 0.65V to 4.35V to charge a 4.2V device. I was planning use a resistor and then a switch that would add another resistor when desired to achieve a further drop to 3.7V. I am unclear on how to control voltage and current at the same time.
I was thinking for the first voltage drop that a resistor of 0.27Ω would cause a drop of 0.65V. Vdrop = 2.4A * R = 0.65V so R = 0.65V/2.4A.
I'm not really sure where to go from here or if this is wildly wrong. Any help would be appreciated.
Thanks,
James