Portable plug-in Power meter

The major problem with most power meters is they don’t give the results in a useable format. kWh and time lapsed : : need converting into which this web site does to compare results with manufactures data.

The same applies with power factor, although the device give us frequency, watts, power factor and volts , it needs as size of capacitor required to be of any use.

You can and enter your own figures or and try again with my sample figures, from a fridge freezer, and an old 11W Ikea compact florescent lamp. My first attempt at a calculator did far more, but I realised there is just no need to know the entire list of what one could work out.  

However some figures as to what to expect would help. An average fridge/freezer will use something like 300 kWh/annum however it needs to be double that figure before one would consider renewing it.

With names like Eco-friendly green power and plug in energy saving monitor one expects these devices to save money. Some times they can highlight power usage one does not expect I was rather surprised to see how much power our sky box used on stand-by. If one switches off items when not in use then these meters do very little. Being able to measure things like voltage without having to stick probes in a socket does allow one to safely gather information. Including one item not advertised and that’s volt drop and with that prospective short circuit current.

Using a load one can quickly get two voltage readings with and without the load. Volt drop divided by current of the device equals the impedance of the circuit and from that volts divided by impedance give prospective short circuit current. Off load volts On load volts Load amps gives us an which in turn gives us an however since the volt meter is only showing the variation in increments of 1 volt and the current is also in increments of 0.02 the accuracy is rather limited try lifting the voltage by one volt or dropping by one volt and that shows how far out the calculation may be.