Answer to Question #90226 in Electric Circuits for Sydney

Question

A portable air compressor rated at 1,600 W draws how many amps from a 12.0 V car battery?

Answer 1

Electricity power P drawn by the compressor is calculated by

$$P=V\cdot I$$

where V is the voltage on car battery, I is the current through the compressor. Substituting P=1,600 W and V=12.0 volts, we get

$$1,600\,W=12.0\,\,volts\cdot I\,amps$$

Now we find the current through the compressor

$$I=\frac{1,600\,W}{12.0\,\,volts}\approx 133.3\,amps$$

So, the electric current through the compressor is 133.3 amps.