Tag Archives: Light-emitting diode

I Like Blue

I didn’t really like the yellowish backlight on my VHF/UHF SWR Meter so I opened it up and grabbed a blue LED to replace it with. I added a small toggle switch as well so I can power the backlight off without having to unplug the power from the back.

It had 12volts already coming in from a power supply so I had to find the right resistor to use on the LED. It is a basic formula:

To calculate the resistor needed for a simple LED circuit, simply take the voltage drop away from the source voltage then use Ohm’s Law.

  • Es is the source voltage, measured in volts (V)
  • Eled is the voltage drop across the LED, measured in volts (V)
  • Iled is the current through the LED, measured in Amperes (Amps/A)
  • R is the resistance, measured in Ohms (Ω)

so..  R=(Es – Eled) / iled

If you don’t want to bother with that you can go HERE

I needed a 560 Ohm resistor to make my LED work on 12volts

I just like the blue backlight!

Image

Wish I had a little smaller switch to use but it gets the job done.

-KG7FDJ


Eternal Orange

Tips and Tricks From James W LePage, KD2DVF

Hackaday

Fresh hacks every day

WREG3 Wx Geek

AMS Meteorologist Austen L. Onek - KG4GKE

Ham Radio Blog PD0AC

Thoughts of a Dutch radio amateur

K5SET Amateur Radio

A great Amateur Radio blog

YB6LD's Blog

A Blog about Ham radio, travel, good food and others

AMSAT-UK

Radio Amateur Satellites

NM5PS

Decidated to the science, art, and magic of amateur radio

Stuff Kids Write

Like stuff adults write. But funnier.

Tech

News and reviews from the world of gadgets, gear, apps and the web

Matt on Not-WordPress

Stuff and things.

KG7FDJ

Journey of a HAM Radio Operator