Tiger6 wrote:SimonCornes wrote:Tiger6 wrote:Should be a 3mm LED, failing that it might be an SMD LED? - either way be careful as they pop easily
Seems like they run on 3 volts anyway - 2 x AA's is convenient.
I used to think that too, until I popped one - the trick is only to touch the contacts momentarily, and not let the magic smoke out by keeping the LED lit for any length of time
Jeez Guys
Sorry for thatt, but I just have to write it off before you burn all the LEDs and your MFUs...
...Why don't you just use the cheapest $ 4-5 multimeter
Here is how to test the LED's ( and diodes also ):
Edit: And you don't have to check the length of the feet in the mounted LEDs. You just do the same with the wires coming out of the LED. The LED supply voltage is 2-4V (3V on average) - depends of LED colour ( see the table below ). And usually this voltage is supplied from the MFU. To be sure, you can connect JST with two free cables and measure the voltage on the LED sockets (but without connecting the LED lights yet). If the voltage is within these limits (2-4V) you connect plus to + and minus to -. That's all. If the supply voltage is too high - solder the resistor using Mr. Ohm's equations. That's all.
WARNING! DO NOT TOUCH / SHORT THE WIRES COMING OUT OF THE MFU. TAKE THE MEASUREMENT ONLY WITH THE MULIMETER CABLES SET AT V DC (by touching each LED wire - one wire from the voltmeter).
- LED_FWD_Volts1.png (86.32 KiB) Viewed 1915 times