I was just thinking if you are on your computer anyway would it just use some of the excess electricity that your computer would have wasted or would it be worse than charging your phone from a charger while using your laptop separately.
I was just thinking if you are on your computer anyway would it just use some of the excess electricity that your computer would have wasted or would it be worse than charging your phone from a charger while using your laptop separately.
Your computer doesn’t “waste” electricity, power usage is on-demand. A PSU generally has 3 “rails”; a 12V (this powers most of the devices), a 5V (for peripherals/USB) and 3.3V (iirc memory modules use this). Modern PSUs are called Switched-mode power supplies that use a Switching voltage regulator which is more efficient than traditional linear regulators.
The efficiency of the PSU/transformer would be what determines if one or the other is more wasteful. Most PSUs (I would argue any PSU of quality) will have a 80 Plus rating that defines how efficiently it can convert power. I am not familiar enough with modern wall chargers to know what their testing at… I could see the low-end wall chargers using more wasteful designs, but a high quality rapid wall charger is probably close to if not on par with a PC PSU. Hopefully someone with more knowledge of these can weigh in on this.