How can i use ADC to measure Current?

In summary, the current shunts available from industrial suppliers can be used to measure voltage in low current applications. You would need an amplifier before the ADC to get a larger voltage.
  • #1
smuscat
31
0
I need please ideas how to use DAC to measure current.Currently I have built DAC to measure voltage, the type i built is the STAIRSTEP RAMP the 8 bit one.
 
Engineering news on Phys.org
  • #2
An ADC measures an analogue voltage a DAC generates one.
Since it measures voltage you have to convert the current into a voltage.
The normal way to do this, eg in a digital multimeter - is to connect a small resistor in series and measure the voltage across the resistor, then use ohm's law to calculate the current. With AC it's a little more complicated - you will have to measure the voltage at many points in the AC cycle and calculate the RMS.


What sort of current / voltage are you looking at?
If you are doing this with very high currents (eg car battery) or high voltages (eg household wiring) you probably want to learn a little more before you try.
 
  • #3
is to connect a small resistor in series and measure the voltage across the resistor

These are known as current shunts and are used everywhere in industry. You can buy them for less than $50 from a lot of industrial suppliers and they usually come pre-calibrated. Most shunts available are 50/50 shunts which basically means 50 amps = 50 millivolts so all you have to do is just shift your decimal point.

http://www.rc-electronics-usa.com/current-shunt.html

current-shuntb_r260_c20.jpg
 
  • #4
DC current i need to measure.I have a problem because it reads a resolution of 5V/256 0.02Volts the voltage is too large i think.Beause the voltage generated by the shunt is too small i think.
 
  • #5
For a real world application you will need an amplifier before the ADC.
In order to get a larger voltage, you would need a larger shunt resistance which will waste energy and reduce the voltage in the circuit.

For somethign like a simple science fair experiment or just to roughly monitor a voltage in a low current application you could use a large eg 1 Ohm resistor.
 
  • #6
Thanks an amplifier like a non inverting one fits well in my circuit.
 

1. What is an ADC?

An ADC, or analog-to-digital converter, is a device that converts analog signals, such as voltage or current, into digital signals that can be read and processed by a digital system.

2. How does an ADC measure current?

An ADC measures current by converting the analog current signal into a digital value. This is done by sampling the current signal at regular intervals and assigning a digital value based on the amplitude of the signal at each sample.

3. What is the resolution of an ADC?

The resolution of an ADC refers to the number of discrete values that the ADC can assign to the input signal. It is typically measured in bits, with higher bit resolutions resulting in more precise digital values.

4. How can I choose the right ADC for measuring current?

When choosing an ADC for measuring current, it is important to consider factors such as the input range and resolution needed, as well as the sampling rate and accuracy of the ADC. Additionally, the type of current being measured (AC or DC) and the desired level of noise reduction should also be taken into account.

5. Are there any limitations to using an ADC to measure current?

While ADCs are commonly used for measuring current, there are some limitations to consider. These include the accuracy and linearity of the ADC, as well as the potential for errors due to noise and aliasing. It is important to carefully select and calibrate the ADC to minimize these limitations.

Similar threads

Replies
31
Views
3K
  • Electrical Engineering
Replies
10
Views
2K
  • General Engineering
Replies
3
Views
1K
Replies
9
Views
1K
  • Electrical Engineering
Replies
14
Views
4K
Replies
14
Views
2K
Replies
5
Views
2K
  • Electrical Engineering
Replies
6
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
3
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
2K
Back
Top