3.7 volts LED with 2 volts - Electronic Circuits Projects Diagrams Free

Grimchuck · 24th April 2003, 10:59 PM

Hello, first i want to say that my knowledge in electronique is very basic.

I have a old NES (nintendo) 8 bits and i want to replace the red LED by a blue LED. Someone check the voltage output for the LED on my NES and told me that it was 1.97 volts. The probleme is that all the blue i can find are 3.7 volts, so i dosent llight on with 2 volts. Does 2 volts bright blue LED exist? and if not, is there a way to light on a 3.7 v LED with 2V?

Ifound that on internet http://nr.stic.gov.tw/ejournal/KB/kb9110_e.pdf

Could something like can help me?

Thanks

Josh · 26th April 2003, 03:04 AM

Have you actually removed the red LED and tried the blue LED in it's place? because it should still work - 3.7V would probably be it's recommended power.

Grimchuck · 26th April 2003, 12:25 PM

No i did not removed the red LED. i plugged the blue LED in parralel with the red and did not light on. In in a electronic shop near my place they told me it was because the LED i must use is 1,85 volts and Blue LED with that voltage dosent exist. They also told me that 3,7 volts LED will not light on with an output of 1.97volts.

Sebi · 26th April 2003, 05:04 PM

Try with removed red LED. I the circuit supply is 5V it will work. If the luminance not enough, decrease the serial resistor, but the supply is only 3V, no chance.

Grimchuck · 26th April 2003, 05:09 PM

the supply is 1.97 volts

Sebi · 26th April 2003, 07:21 PM

From what battery coming 1.9V? I think You've measured this voltage on red LED. The circuit supply must be 3 or 5V. Have You changed the LED and so measured?

Grimchuck · 26th April 2003, 07:53 PM

here is the thing http://pages.infinit.net/grimchuc/im...rswitch_01.jpg http://pages.infinit.net/grimchuc/im...rswitch_02.jpg
i measured the power on 2 pins on the left of the circuit and it gave me 1.97 volts

Sebi · 27th April 2003, 07:58 AM

O.K. On this panel You can't measure the supply voltage, only the LED voltage. Try change the LED, no risk.

bogdanfirst · 27th April 2003, 03:15 PM

it is very likely that the led has a series resistor in series with it. look at the wire coming from the led and going to the other board. what it is connected to. follow the copper wire line and you might go to a resistor.
you need to put a smaller value resistor in place of that, or another resistor in paralel with it.
but first remove the red led and put the blue led in place.see if it works

Grimchuck · 27th April 2003, 04:25 PM

Thanks, i will try that

24th April 2003, 10:59 PM	(permalink)
Grimchuck New Member	3.7 volts LED with 2 volts Hello, first i want to say that my knowledge in electronique is very basic. I have a old NES (nintendo) 8 bits and i want to replace the red LED by a blue LED. Someone check the voltage output for the LED on my NES and told me that it was 1.97 volts. The probleme is that all the blue i can find are 3.7 volts, so i dosent llight on with 2 volts. Does 2 volts bright blue LED exist? and if not, is there a way to light on a 3.7 v LED with 2V? Ifound that on internet http://nr.stic.gov.tw/ejournal/KB/kb9110_e.pdf Could something like can help me? Thanks

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26th April 2003, 03:04 AM	(permalink)
Josh Experienced Member	Have you actually removed the red LED and tried the blue LED in it's place? because it should still work - 3.7V would probably be it's recommended power.

26th April 2003, 12:25 PM	(permalink)
Grimchuck New Member	No i did not removed the red LED. i plugged the blue LED in parralel with the red and did not light on. In in a electronic shop near my place they told me it was because the LED i must use is 1,85 volts and Blue LED with that voltage dosent exist. They also told me that 3,7 volts LED will not light on with an output of 1.97volts.

26th April 2003, 05:04 PM	(permalink)
Sebi Experienced Member	Try with removed red LED. I the circuit supply is 5V it will work. If the luminance not enough, decrease the serial resistor, but the supply is only 3V, no chance.

26th April 2003, 05:09 PM	(permalink)
Grimchuck New Member	the supply is 1.97 volts

26th April 2003, 07:21 PM	(permalink)
Sebi Experienced Member	From what battery coming 1.9V? I think You've measured this voltage on red LED. The circuit supply must be 3 or 5V. Have You changed the LED and so measured?

26th April 2003, 07:53 PM	(permalink)
Grimchuck New Member	here is the thing http://pages.infinit.net/grimchuc/im...rswitch_01.jpg http://pages.infinit.net/grimchuc/im...rswitch_02.jpg i measured the power on 2 pins on the left of the circuit and it gave me 1.97 volts

27th April 2003, 07:58 AM	(permalink)
Sebi Experienced Member	O.K. On this panel You can't measure the supply voltage, only the LED voltage. Try change the LED, no risk.

27th April 2003, 03:15 PM	(permalink)
bogdanfirst Experienced Member	it is very likely that the led has a series resistor in series with it. look at the wire coming from the led and going to the other board. what it is connected to. follow the copper wire line and you might go to a resistor. you need to put a smaller value resistor in place of that, or another resistor in paralel with it. but first remove the red led and put the blue led in place.see if it works

27th April 2003, 04:25 PM	(permalink)
Grimchuck New Member	Thanks, i will try that