In ammeter application, I am using CT for step down current value. primary current range is 150mA to 5A an i get secondary current 60uA to 2mA. what kind of circuitry i have to add for low current measurement before giving it to ADC of microcontroller?

 

hi vinoda,
Welcome to AAC.
What is the value of the burden resistor on the output of the CT.?
E

 

hi vinoda,
Welcome to AAC.
What is the value of the burden resistor on the output of the CT.?
E

30

 

For one thing, if you run multiple turns through the CT, it will increase the output. That could help.

 

hi,
Across the 30R, you should measure approx 1.8mV thru 6mV.
Is the ADC of the MCU 3.3v or 5v. ?

E

 

For one thing, if you run multiple turns through the CT, it will increase the output. That could help.

i increased primary number of turns to three. but unable to measure current less than 1mA

 

hi,
Across the 30R, you should measure approx 1.8mV thru 6mV.
Is the ADC of the MCU 3.3v or 5v. ?

E

internal voltage reference 1.1v used for ADC measurement. controller voltage 3.3V

 

hi,
The simple option would be a OPA, gain say 1.1v/6mV, approx gain 183.
I am assuming unidirectional DC current.?

 

could you suggest any circuit schematic?

 

could you suggest any circuit schematic?

What type of OPA's do you have in your bits box.?
E

 

Have you tried increasing the value of the burden resistor?

 

Have you tried increasing the value of the burden resistor?

i am using CT1231. recommended secondary burden for this ct is 30 ohm.