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Made it simpler
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If you have a power supply with adjustable current limit (like this one), then it becomes very easy.

  1. Set the output voltage to around 5V.
  2. Dial and dial the current limit all the way down.
  3. Connect the diode directly to V+ and COMthe power supply, with no resistor. Don't worry! You've already limited the current!
  4. Dial up the current until it reaches your target (say, 20mA).

The power supply is limiting the current through the LED to the dialed-in limit. The voltage display will show you what voltage is required to push that much current. That's your forward voltage!

If you have a power supply with adjustable current limit (like this one), then it becomes very easy.

  1. Set the output voltage to around 5V.
  2. Dial the current limit all the way down.
  3. Connect the diode directly to V+ and COM, with no resistor. Don't worry! You've already limited the current!
  4. Dial up the current until it reaches your target (say, 20mA).

The power supply is limiting the current through the LED to the dialed-in limit. The voltage display will show you what voltage is required to push that much current. That's your forward voltage!

If you have a power supply with adjustable current limit (like this one), then it becomes very easy.

  1. Set the output voltage to around 5V and dial the current limit all the way down.
  2. Connect the diode directly to the power supply, with no resistor. Don't worry! You've already limited the current!
  3. Dial up the current until it reaches your target (say, 20mA).

The power supply is limiting the current through the LED to the dialed-in limit. The voltage display will show you what voltage is required to push that much current. That's your forward voltage!

Removed an unnecessary step, thanks to EM Fields
Source Link
bitsmack
bitsmack
  • 17.1k
  • 11
  • 58
  • 119

If you have a power supply with adjustable current limit (like this one), then it becomes very easy.

  1. Set the output voltage to around 5V.
  2. Dial the current limit all the way down.
  3. ShortConnect the diode directly to V+ and COM terminals, with a wireno resistor. Don'tDon't worry! You've already limited the current!
  4. Dial up the current until it reaches your desired LED currenttarget (say, 20mA).
  5. Now, disconnect the wire and put the LED in place.

The power supply will limitis limiting the current through the LED to the predialed-setin limit. The voltage display will show you what voltage is required to push that much current. That's your forward voltage!

If you have a power supply with adjustable current limit (like this one), then it becomes very easy.

  1. Set the output voltage to around 5V.
  2. Dial the current limit all the way down.
  3. Short the V+ and COM terminals with a wire. Don't worry! You've already limited the current!
  4. Dial up the current until it reaches your desired LED current (say, 20mA).
  5. Now, disconnect the wire and put the LED in place.

The power supply will limit the current through the LED to the pre-set limit. The voltage display will show you what voltage is required to push that much current. That's your forward voltage!

If you have a power supply with adjustable current limit (like this one), then it becomes very easy.

  1. Set the output voltage to around 5V.
  2. Dial the current limit all the way down.
  3. Connect the diode directly to V+ and COM, with no resistor. Don't worry! You've already limited the current!
  4. Dial up the current until it reaches your target (say, 20mA).

The power supply is limiting the current through the LED to the dialed-in limit. The voltage display will show you what voltage is required to push that much current. That's your forward voltage!

Source Link
bitsmack
bitsmack
  • 17.1k
  • 11
  • 58
  • 119

If you have a power supply with adjustable current limit (like this one), then it becomes very easy.

  1. Set the output voltage to around 5V.
  2. Dial the current limit all the way down.
  3. Short the V+ and COM terminals with a wire. Don't worry! You've already limited the current!
  4. Dial up the current until it reaches your desired LED current (say, 20mA).
  5. Now, disconnect the wire and put the LED in place.

The power supply will limit the current through the LED to the pre-set limit. The voltage display will show you what voltage is required to push that much current. That's your forward voltage!