Measuring the current used in a power supply?

[24Volts]

hello,

I have a power supply converter that converts 120VAC to 3.3VDC at 1A.

I would like to know (without measuring with an ammeter) when I am drawing 800 milliampères or more. When 800+ milliampères are used, I want to light up a led to indicate that the power supply has attained 80% of its capacity.

How can I do this?

All circuit ideas are welcome!

Thanks

 

[Chemelec]

If you want the output STABLE at 3.3 Volts,
Than Without seeing a Schematic of your power supply, it would not be possible.

 

[BobK]

If you want the output STABLE at 3.3 Volts,
Than Without seeing a Schematic of your power supply, it would not be possible.

True, but if you can tolerate 3.29 V it can be done.

You need a low value (say 0.01Ω) resistor and a comparator to do this. It would drop 8mV at 800mA.

Bob

 

[24Volts]

Hi guys,

I was thinking of using the INA169 to achieve current sensing:

https://www.sparkfun.com/products/12040

the power supply I want to monitor is located at:

https://www.digikey.ca/products/en?keywords=pbo-5-s3.3

I was wondering if this would work?

Thank you for your help

 

[Chemelec]

Hi guys,

I was thinking of using the INA169 to achieve current sensing:

https://www.sparkfun.com/products/12040

the power supply I want to monitor is located at:

https://www.digikey.ca/products/en?keywords=pbo-5-s3.3

I was wondering if this would work?

Thank you for your help

Yes that will work, But Depending on the Value of the Sensing Resistor "RS", You get a Voltage Drop.

This is Basically the Same as what "BobK" Said.

And with your Power Supply, there are No Other Options.

 

[24Volts]

Yes that will work, But Depending on the Value of the Sensing Resistor "RS", You get a Voltage Drop.

This is Basically the Same as what "BobK" Said.

And with your Power Supply, there are No Other Options.

Ok thanks for you help!
24V