What is 60 watts of voltage

How can you explain the difference between watts and volts?

Question from:
Date: 13.11.2003

An eight year old student asked me to explain the difference between watts and volts. I'm looking for a very simple explanation for these two terms.

Thanks in advance.


Answer from:
Date: 1.12.2003

This child's question is not an easy one to answer. It is very difficult to define voltage or power in a simple way. I'll try once and you'll tell me if it's understandable.

We start with a statement:

                                                               
  • A 230V / 60W incandescent lamp that is built into a circuit with a 3V battery does not light up.
  •                                                                                                        
  • A 230V / 60W incandescent lamp that is connected to a socket via a cable, i.e. to the 230V power supply, lights up.
  •                                                                                                        
  • A 3.5V / 200mA light bulb (which corresponds to a power of 0.7W) that would be connected to the 230V power supply would be broken immediately (you shouldn't do that under any circumstances).
  •                                                                                                        
  • A 3.5V / 200mA light bulb that is built into a circuit with a 3V battery lights up.

What can we conclude from this? The voltage on an electrical device (in this case, a lightbulb) indicates how many volts this device will function properly (the applied voltage should be pretty much the same). The wattage on the device, on the other hand, indicates what the device can "deliver" or consume (from an electrical point of view).


Answer from:
Date: 6.5.2010

To explain the voltage and power, I would suggest using the behavior of water falling down a waterfall as an image (which, by the way, is largely physically correct).

The height from which the water falls corresponds to the tension. A large, heavy waterwheel cannot be driven quickly if a droplet only falls occasionally. A lot of water has to fall down at the same time. On the other hand, if the height is only very small (maybe 1 cm), it won't work either. So you need a sufficiently high altitude and a sufficiently large amount of water.

The power measured in watts is something that is made up of the altitude (corresponding to the voltage measured in volts) and the water flow (the current expressed in amperes) (more precisely, it is the product of both).

You can now follow up on the light bulb example from Edith Saltiel's previous answer: A 230V / 60W light bulb (or a vacuum cleaner, a washing machine, etc.) is like a large, heavy water wheel, a small light bulb like a tiny toy water wheel made of paper . Such a small, light wheel can also be driven with little water that falls from only a small height. If you drop the water on it from too high a height, it will break.
 

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