current measurement to send to a comparator

Thread Starter

Hugo100

Joined May 6, 2022
4
Good day everyone,
I´m building a very basic circuit, 4.5V., 1 fixed resistance, 1 variable resistance. I want to measure the current based on the changes the variable resistance have. What would you recommend? thank you in advance for taking the time to help.
 

Ian0

Joined Aug 7, 2020
9,677
Measure the voltage across the fixed resistance. Divide by the value of the fixed resistance.
(That assumes that the two resistances are in series, but you didn’t say how they are connected)
 

Thread Starter

Hugo100

Joined May 6, 2022
4
Measure the voltage across the fixed resistance. Divide by the value of the fixed resistance.
(That assumes that the two resistances are in series, but you didn’t say how they are connected)
That is actually a good point. they will be connected in series to have a voltage variation. Is there a microprocessor that you know that can measure that change in voltage and send a signal to a comparator to activate another circuit?
 

Ian0

Joined Aug 7, 2020
9,677
That is actually a good point. they will be connected in series to have a voltage variation. Is there a microprocessor that you know that can measure that change in voltage and send a signal to a comparator to activate another circuit?
Most of them.
But why do you need a microprocessor to send the signal to the comparator, when you can just connect the signal to the comparator?
 

Thread Starter

Hugo100

Joined May 6, 2022
4
Most of them.
But why do you need a microprocessor to send the signal to the comparator, when you can just connect the signal to the comparator?
Hi Ian0! Thank you for your suggestion. I looked at different options and I think this can work. What I want to do is to measure a voltage and send it to a comparator and if the value is above what I will specify, I want to turn on an LED. if it is below, I want to turn on a different LED. Which comparator do you recommend? Can this comparator send a signal to turn on the LED or can you suggest something? Thank you so much for your kind attention
 

WBahn

Joined Mar 31, 2012
29,979
So will one of two LEDs always be on? That makes things a lot simpler since you can wire one LED to turn on with a LO signal and the other to turn on with a HI signal.
 
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