Designing an AC Ammeter with 0.15V Voltage and Currents of 200mA, 500mA, 1A

[micul1987]

Hello all!

I must design an ac ammeter which uses successive approximation ADC,has a specified voltage of 0,15V and individual entrance resistors for measuring currents of 200mA,500mA,1A.

Any suggestions on how to build such a device would be highly appreciated!

 

[berkeman]

Hello all!

I must design an ac ammeter which uses successive approximation ADC,has a specified voltage of 0,15V and individual entrance resistors for measuring currents of 200mA,500mA,1A.

Any suggestions on how to build such a device would be highly appreciated!

Welcome to the PF. What can you tell us about A/D conversion? What functional blocks do you need to have outside the ADC for signal conditioning? How do you plan to handle the AC aspects of this design problem? What frequency range AC do you need to handle, and how many bits will you use in your ADC?

 

[micul1987]

I have found the AD572 which basically is a 12-bit successive approximation integrated circuit a/d convertor.

 

[vk6kro]

You could have a look at this post which describes an AC ammeter (1st diagram):

https://www.physicsforums.com/showpost.php?p=2503935&postcount=5

Read the whole thread here:
https://www.physicsforums.com/showthread.php?t=365063

The shunt is optional and the current meter shown just works on DC.

The shunt could be across the meter if you like. This gives a more linear readout for the meter but results in some drop in the supply voltage due to diode drops.

For an A to D converter, the meter input should be filtered with a large capacitor to get a steady readout.

 

[DeeNos]

Hello,

Designing an AC ammeter with a specified voltage of 0.15V and currents of 200mA, 500mA, and 1A is certainly a challenging task. One possible approach could be to use a successive approximation ADC (analog-to-digital converter) as mentioned. This type of ADC works by comparing an unknown input signal to a known reference signal and gradually narrowing down the range of the unknown signal until a precise measurement is achieved.

To measure the desired currents, you will need to use individual entrance resistors for each current range. These resistors will help to limit the amount of current flowing through the circuit and prevent damage to the ADC. The values of these resistors will depend on the specific requirements of your circuit and the capabilities of the ADC.

In addition to the ADC and resistors, you will also need to include other components such as amplifiers and filters to ensure accurate and reliable measurements. The design of these components will also depend on the specific requirements of your circuit and the type of AC signal you are measuring.

I recommend consulting with a professional electrical engineer or conducting further research to ensure that your design meets all necessary specifications and safety standards. Good luck with your project!