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just for indication.
at 12V you better use 4K7
On Mon, Nov 6, 2017 at 1:42 PM, Michael Hagen <motdog@...>
Using 680 ohms will
really make the LED bright. I = (12V - 3.3V ) / 680. Most
work real nice on just a few ma. 2.2K should give nearly 5
ma. What folks are saying is an LED is not "operated" or
"biased" with voltage. You put a current thru them, and the
voltage is just a result. You get what you get!
The current limit
resistor is picked for how bight you desire it to be. The
3.3V spec will be the approximate voltage drop at a given
If you were running on
a battery, you might try only 1 or 2 ma.
Just a thought, most
take 20 ma. OK. For an experiment, try 10K and then 1K?
On 11/5/2017 9:52 PM, Prathap Naidu
can use a dual color LED with 3 leads, centre is common gnd.
have used a standard 3mm LED , you can also use 5 mm if you
need, but the 3 mm is quite Ok
680 ohms is the dropping and current limit resistor, I have
tapped the 2 wires from the K1 relay which alternates the
+12V between Rx and Tx
BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of
Sent: Monday, November 06, 2017 11:11 AM
Subject: Re: [BITX20] RX and TX LED
Thank you VU2POP. Is the yellow wire
for RX and the green wire for TX and then the 680 ohm
resistor goes to ground? Is the LED 12 volts? I was
planning on using a Red 3.3 volt LED to indicate TX and a
green 3.3 volt LED to indicate RX
On Mon, Nov 6, 2017 at 12:37 AM
Prathap Naidu <vu2pop@...> wrote:
attached pics, solder 2 wires below the K1 relay
as shown, then to the Dual color LED , the centre
of the LED goes to ground thru a 680 Ohms
On Behalf Of Ben Piecora
Sent: Monday, November 06, 2017 2:51 AM
Subject: [BITX20] RX and TX LED
anybody tell me a way I can pull voltage from the
board for an LED on RX and then pull voltage from
the board for a TX LED and turn off the RX LED?
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
PayPal ID "MotDog@..."