Is there a way to measure the electric current or power of the
whole computer or its components using software? Voltage can be
measured, and I am wondering why not with the current/power.
Voltage can only be measured because most modern machines have
hardware built-in that can do so; the software simply talks to
the hardware over e.g. I2C and reads the values from it. No
equivalent hardware for measuring current is in modern
computers.