Does electrical appliances draw more current or less current during low voltage? Why?

P = V I cos(phi) Here V is voltage, I is current and Cos(phi) is Load Power Factor The standard supply code in India is 230V voltage, 5A-50Hz current and 0.8 power factor. Hence in a normal electric circuit to maintain a constant Power(P) Voltage(V) & I(Ampere) are inversely proportional. Therefore, voltage to decrease, current has to increase (considering constant load power factor) thus more current will be drawn during low voltage. Thank you! read less

There are two kinds of appliances: 1) Without Motor (resistive load) and 2) With Motor (inductive load). Appliances without motor include Bulbs/Tube lights/CFLs, water heaters and room heaters / TVs/Music Systems/DVD/Home Theatre/ Laptops/Phones. Appliances with motor include Air Conditioners/Refrigerators/Ceiling Fans/Mixer Grinders/Pumps/Washing Machines. When the voltage is less, less current flows through them. When voltage is more, more current will flow through them. So when voltage is less, the output of these appliances will be less or the bulb will give less light, room heater will heat less, water heater will heat slowly. And as the bulb will give lesser light the power consumption of the bulb will be less. Most electronics like TVs, DVD players, etc do not work at 230 V. These appliances have an internal device called SMPS (Switch Mode Power Supply) which converts incoming 230 V to 12V or 24V (whichever is required by the appliance). The power consumption of electronic products does not change with voltage changes. All appliances with motors have an operating voltage range. Appliance like a ceiling fan have much larger operating voltage range and thus they are able to work even at lower voltages. But appliances like air conditioners have very small operating voltage range and thus they do not work at low voltages. If the voltage provided to them is lower than their operating voltage range, then either they will not start at all, and if they are already running, they will start producing a humming sound. This humming sound happens as these motors draw more current to run the system. At high voltages these appliances draw more current only at the time of starting, but once they reach steady state the current is much less. read less