Simple led circuit

Fulbrog · Jul 15, 2010

Hi. I have just begun studying electronics and i saw this image **broken link removed**
on https://www.electronicsteacher.com/
Why is the resistor placed after the led and not before?

Transistorman · Jul 15, 2010

you will know that later , after you mastering electronic , you will understand that

wizard · Jul 15, 2010

Fulbrog said:
Hi. I have just begun studying electronics and i saw this image **broken link removed**
on Electronic Tutorials, Electronic Kits, Electronic Tutorials,Electronic Hobby Kits, News
Why is the resistor placed after the led and not before?

Because both LED and Resistor are IN SERIES so it does not matter which one to be placed bellow or above. The resistor is there to limit the voltage across the LED to about 3V or so and it does not matter if it is connected bellow/Above the LED because the circuit is a SERIES circuit.

Reloadron · Jul 15, 2010

Hi Fulbrog;

The following is taken directly from your link:

People often think that the resistor must come first in the path from positive to negative, to limit the amount of current flowing through the LED. But, the current is limited by the resistor no matter where the resistor is. Even when you first turn on the power, the current will be limited to a certain amount, and can be found using ohm’s law.

The purpose of the resistor is to limit the current flow through the LED. Since the resistor is in series with the LED it really matters not where it is placed. The resistor will do the same thing be it on the Cathode or Anode side of the LED.

Ron

MikeMl · Jul 15, 2010

Fulbrog said:
...
Why is the resistor placed after the led and not before?

It matters NOT!

Math analogy:

C = A + B = B + A

wizard · Jul 16, 2010

Reloadron said:
Hi Fulbrog;

The purpose of the resistor is to limit the current flow through the LED. Ron

I hope this does not make the OP confused, I told the resistor is there to limit the voltage across the led, which is the FINAL goal of limitting the current of the circut.

geboy · Jul 17, 2010

It does not matter where the resistor is placed.But what does matter is the value of the resistor.
The value should not be too low to burn out LED,and not too high so that the LED does not glow

Reloadron · Jul 17, 2010

The original poster's drawing came directly from this page and things are covered fairly well. There isn't much room for confusion as things are pretty well spelled out in the link. I figure he should do just fine.

Ron

Simple led circuit

Fulbrog

New Member

Transistorman

Member

wizard

Member

Reloadron

Well-Known Member

MikeMl

Well-Known Member

wizard

Member

geboy

New Member

Reloadron

Well-Known Member

Similar threads

Simple led circuit

New Member

Member

Member

Well-Known Member

Well-Known Member

Member

New Member

Well-Known Member

Similar threads

Privacy & Transparency

Privacy & Transparency