Current clamp View larger

Current clamp

Current clamp with a microcontroller.

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Data sheet

Supply voltage5 Volts

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Before we start describing the circuit, we have to make something clear. In the dictionary, the clamp is defined as “an instrument whose extreme ends are joined together to hold something”.

If we take this definition as true, than our circuit couldn’t be called current clamp, since we don’t hold anything with its extreme ends.

However, if we ask an electrician: Do you know what the current clamp is?, the answer can be the following: “It is an electronic device that serves to measure the amperes that circulate through a cable by placing a ring around it”.

Quite so, our current clamp is an electronic circuit governed by a PIC microcontroller which we shall use to measure the volts and the amperes and to calculate the watts we are consuming.

The component which will take the place of the “clamp” will be a reduced dimension transformer, with the hole in the centre, and it will capture the quantity of the current that circulates through the cable which surrounds.

Current clamp transformer

The power at the transformers output will be proportional to the current that circulates through the cable which it surrounds.
The circuit is meant to measure how much energy we are consuming at home. To do this, we will reeve the electricity cable from the house entrance through the hole in the transformer’s centre.

The transformer’s output will be connect to the microcontroller which will do the rest of the work. It will tell us how many amperes are we consuming, the power of the electric current and the watts that we spend at that moment.

Also, we have completed the assembly with the measures of the maximums of amperes, volts, and watts.

Finally, we have added a sound alarm as well, which will inform us when we are close to the contracted power limit. If we surpass it, we know that our general differential will cut our household electricity because of the excessive consumption.

If you are thinking in other possible ways to apply our circuit, you should know that it can only be used to measure alternating current, not direct current.

A photo of the current clamp which measures the volts, amperes and watts that we are consuming, installed in the household.

Current clamp photo

The circuit is in its final phase and we shall be displaying it on this web page shortly.

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