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basic question about current

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lats

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Hi,
I'm designing a ampere meter (to measure upto 5A current) using a CT (current transformer) with ratio 1:2500, which means for 5A input i'll get 2mA current and with a 50 ohms burden resistor i'll get 0.1 volts for 5A current. Will this 0.1 volts be peak value or RMS?
 

Davood Amerion

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usualy because of 5A is rms value then C.T. output current and voltage will be rms value.
 

lats

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ok. actually i want to measure and display three phase currents with single display. So should i feed these three analog voltages (0 - 0.1 v) to a analog multiplexer (like cd4051) and then feeding the output of analog multiplexer to a peak detector and then to an op-amp (to increase the gain) i.e. to make 0- 5v range and then to an ADC. the three different inputs can be selected one at a time through micro-controller.

and also thanks for replying previously
 

Davood Amerion

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may be better to amplify and rectify with 3 op-amp and connect there peak values to microcontroller.
some of microcontroller have ADC on chip, such as PIC16F873-4-6-7 or ATMEGA8,16.

Regards,
Davood
 

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