Very simple resistor question - Electronic Circuits Projects Diagrams Free

Myrmidon · 5th January 2008, 07:00 PM

Hello all.

I have a very basic question, halfway through my 1st year doing electronics and i'v asked my lecturer but i forgot his answer and i don't go back to wednesday.

Ok, simple circuit powering an led say. Generally you would put in the required value resistor before the led. However, in a few internet circuits i'v came across, the resistor is AFTER the led.

I'm assuming this is still limiting current but i don't get/can't remember how this is so.

So basically, can someone answer why a resistor would come after an led.

Cheers.

BeeBop · 5th January 2008, 07:07 PM

Quote:

Originally Posted by Myrmidon

Hello all.

I have a very basic question, halfway through my 1st year doing electronics and i'v asked my lecturer but i forgot his answer and i don't go back to wednesday.

Ok, simple circuit powering an led say. Generally you would put in the required value resistor before the led. However, in a few internet circuits i'v came across, the resistor is AFTER the led.

I'm assuming this is still limiting current but i don't get/can't remember how this is so.

So basically, can someone answer why a resistor would come after an led.

Cheers.

Hi Myrmdon,
In a series circuit, the same current flows through all parts of the circuit, hence the resistor limits the current through all parts of the loop, including the LED.

henrybot · 5th January 2008, 07:08 PM

If you're increasing a branch resistance (regardless of where the resistor is in the branch), you are decreasing current through that branch.

Myrmidon · 5th January 2008, 07:54 PM

Ah! Thank you, i thought that might be the case. It was starting to come back to me there.

Cheers!

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5th January 2008, 07:00 PM	(permalink)
Myrmidon	Very simple resistor question Hello all. I have a very basic question, halfway through my 1st year doing electronics and i'v asked my lecturer but i forgot his answer and i don't go back to wednesday. Ok, simple circuit powering an led say. Generally you would put in the required value resistor before the led. However, in a few internet circuits i'v came across, the resistor is AFTER the led. I'm assuming this is still limiting current but i don't get/can't remember how this is so. So basically, can someone answer why a resistor would come after an led. Cheers. __________________ Hardcore Dance Music

5th January 2008, 07:08 PM	(permalink)
henrybot	If you're increasing a branch resistance (regardless of where the resistor is in the branch), you are decreasing current through that branch.

5th January 2008, 07:54 PM	(permalink)
Myrmidon	Ah! Thank you, i thought that might be the case. It was starting to come back to me there. Cheers! __________________ Hardcore Dance Music