I just started my journey into electronics and have successfully built a 2 digit 7 segment counter (using IC 40110 and a pushbutton) on a breadboard. I used the 3.3V and ground pins of Arduino to power my breadboard.
I am trying to make a standalone circuit which can be powered by a battery. The goal is to increase the lifetime as long as possible while the circuit serves its function. Once I do this on my breadboard, I plan to design PCB for this circuit. But I feel stuck by not understanding the best way to power my circuit and need your help on this.
Q) How can I determine the power consumption of circuit? Should I measure the current and votlage across each of the 7 LED segments and sum their product?
Q) Is determining the input voltage of my circuit important? If so, how can I determine the minimum input voltage required? (I assume I should go for the minimum operating voltage so that I can reduce power consumption)
I researched online and found few ways of doing this:
A) Use 9V battery connected to this power supply module:
B) Use 9V batter and connect it to a down converter
Method A seems to be the easiest way but it uses linear regulatobrs which is less efficient than the buck converter. Q) Apart from simplicity, when/why would anyone use this?
I think Method B is the way to go because they are efficient than linear regulators but I don't know how much difference it will make. Q) How can I compute and compare these 2 methods?
Thanks a lot in advance!