Variable Resistor

Greetings All,
Is there an electronic element that with increasing current, resistance increase?
like VDR but about current instead of voltage
thanks a lot :slight_smile:

Resistance of a PTC increases when it gets hot from the current flowing through it.
A practical example is the self-healing USB polyfuse on your Uno/Mega.
Leo..

Wawa:
Resistance of a PTC increases when it gets hot from the current flowing through it.
A practical example is the self-healing USB polyfuse on your Uno/Mega.
Leo..

Thanks Wawa, I want this component for limiting a photodiode current that doesn't go higher than a specific value. Is it practical?

Not really. What's wrong with using a normal resistor?

septillion:
Not really. What's wrong with using a normal resistor?

OK, thanks for assistance :slight_smile:

What are you trying to do?

Hi,
If you are trying to measure the output of a Photo-transistor, the last thing you need is the series resistor to vary with current.

You will be using a FIXED resistance to convert the Photo-transistor current to a readable voltage.

Use OHMs law to check for max current, but more importantly research hoe how Photo-transistors work and how you use them.

Tom.... :slight_smile:

TomGeorge:
Hi,
If you are trying to measure the output of a Photo-transistor, the last thing you need is the series resistor to vary with current.

You will be using a FIXED resistance to convert the Photo-transistor current to a readable voltage.

Use OHMs law to check for max current, but more importantly research hoe Photo-transistors work and how you use them.

Tom… :slight_smile:

Thanks guys