As we have talked about in the previous sections, we are working with DC currents here, which means we are either using batteries or some other power supply we plug into the wall to convert AC to DC. In any case, our projects require a specific operating voltage and a certain amount of current.
Some devices require specific voltages to operate correctly; this voltage is called “operating voltage” or V, and needs to be provided by your power supply. A different voltage (generally, if your voltage is too high) will potentially ruin your device.
Many devices (arduino, raspberry pi) have regulators and will only use the amount of current they need even if more current is provided. In the case of other devices (drivers, steppers), if more current is provided than needed, this will lead to heat and burning.
In all cases, the power supply must provide the correct operating voltage or voltages, and the sum of the currents required by all devices.