The Stovebolt Site Forums The Shop Area The Electrical Bay Do I need a diode for this

Hopefully I can get the pic to post
Do I need a diode for these tiny lights I plan to use for blinker indicators on the dash on my 52 Chevy truck it has a 12 volt system and no other led lights

If you mean a resistor, I don't think so, as long as the flasher works correctly. If you were to put all LED's in, then you may need a resistor somewhere in the circuit. BTW, an LED is a Light Emitting Diode.

Thanks for replying wasn’t sure if had to add or change some

There are LEDs made especially to use with 12v and they will have a tiny resistor either built in the LED or in the wiring. An LED will have a + wire and a - wire. If you ground the - wire and touch the + wire to 12v + for just a bit you can tell. If it glows very brightly (too brightly) it isn't a 12v LED and if kept connected will burn out rapidly. If it is a 12v LED, it will glow at a nice even level. I used leds in the GPS and the programmable (pulse output) electronic speedometers I made for the AD. I used green for the directional indicators and red for the hi-beam. Good luck!

Afterthought...if you have regular LEDs (not made for 12v) you can determine the amount of resistance needed to operate them on 12v by connecting a variable resistor (also known as a potentiometer) with a value of 5K ohms between the LED lead (either + or -) and either ground or the positive 12v source. Usually 1K ohm resistor is good, but if you don't know how your LED was built, you can figure it out with the variable resistor. Simply start at 5K of resistance (all the way to the right or left, depending on which way you connected the variable resistor) and turn slowly until you reach the desired degree of "glow" you want. Use a handheld meter to measure the variable resistor and also to know which resistor value to use when you get your desired brightness. Standard LEDs are not expensive at all (often you can buy 300 for $10 or so) and come in many colors so you could use yellow, orange, red, green, blue, white, purple...lots to choose from here.