Measuring power consumption cheaply using a resistor inline?
Posted: Sun Jan 03, 2010 3:29 pm
I see alot of people measuring power consumption with Kill-a-Watt, UPS readings, or using other devices. All along, I've been measuring my power consumption using a very cheap and simple technique.
I modified a power cable with a 1 ohm 10 watt resistor inline of the neutral wire (not the live wire, because that would be dangerous). Then by measuring the voltage drop over the resistor, you can calculate the current that is flowing and then the power consumed by whatever is plugged into the modified power cable.
Danger aside, I am just wondering how accurate this method would be compared to the other methods especially with power factor taken into account? I'll admit I wasnt paying much attention in physics class during the power factor section =( Are there other things to take into consideration? I measured the power consumption of various lamps and this method seems accurate enough.
I modified a power cable with a 1 ohm 10 watt resistor inline of the neutral wire (not the live wire, because that would be dangerous). Then by measuring the voltage drop over the resistor, you can calculate the current that is flowing and then the power consumed by whatever is plugged into the modified power cable.
Danger aside, I am just wondering how accurate this method would be compared to the other methods especially with power factor taken into account? I'll admit I wasnt paying much attention in physics class during the power factor section =( Are there other things to take into consideration? I measured the power consumption of various lamps and this method seems accurate enough.