What type emonTx do I need?

This is may be the most stupid question but I am not even sure if I need emonTx for my project.
I am working on a project in which I want to simply measure apparent power and display it on serial monitor as I am using arduino. I understood circuit connections of CT with arduino. But I am not sure about this emonTx. In the circuit diagram its not appearing anywhere.Can someone please explain me if I need it and why and if yes what could be the choice.

The circuit diagram of both the emonTx and the emonTx Arduino Shield is available, you need to look under Resources and the Wiki.

An emonTx uses the same processor as the basic Arduino (Atmel ATMega328P) but also on the PCB are the input circuits for a voltage input and 4 current inputs, all via safety isolating voltage and current transformers respectively.

You have 3 choices:

  1. Build your own input circuits on prototype board, following the circuit diagrams in Building Blocks, and connect that to your Arduino board.
  2. Buy an emonTx Shield to add to your Arduino.
  3. Buy an emonTx V3.4.

If you only want a serial monitor, you won’t need the radio module, so choose the “No RF” option if you buy the emonTx or emonTx Shield from the Shop.

It is likely that you will get better, more accurate measurements if you use the emonTx (not the emonTx Shield).