A peak detector circuit was​ needed as the output of the current sensor was a waveform. This waveform can be seen in picture A.

 

Firstly, a P-Spice simulation for the peak detector circuit was created. The full circuit can be seen in picture B. The components used are:

• 1 x 10kΩ resistor

• 1 x 1MΩ resistor

• 1 x 10uFarad Capacitor

• 1 x 1N4148 Diode

• 1 x ua741 op amp

The op-amp was not used to amplify the output as it would traditionally be used, but instead the op-amp was to make it so that there would be no diode drop across the diode. As the voltages that come out of the current sensor are very small (104mV out of the current sensor was equivalent to 1A of current), a diode drop would completely ruin the results so therefore the op-amp was needed to get rid of this diode drop of 0.7V. 

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The output of the P-Spice simulated circuit can be seen in picture C. The green waveform is the simulated output from the current sensor and the red line represents the output from the peak detector circuit. 

 

The peak detector circuit works in the following way; the capacitor charges up until it reaches the highest voltage/peak in the circuit. The capacitor then holds this value until it reaches the next highest voltage/peak. The capacitor also discharges over time as to not hold the same peak for too long and give false high readings. The values of the resistor R1 and the capacitor C1 needed to be chosen to created a suitable discharge time for the peak of the circuit. The values of 1000KΩ for the resistor and 10uFarads for the capacitor were chosen as they gave the most suitable discharge time.

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Finally the output from the peak detector circuit can be seen in picture D.