JSL-502 Series 5V Tolerant 5mm LEDs (HCOPTO0057-59)

[admin]

Available in several colours, these 5V tolerant LEDs are an excellent addition to any hobbysists component collection. As these are 5V tolerant, they're harder to blow up than standard LEDs, making them perfect for beginners, and also for schools! These LEDs are available in Red (HCOPTO0057), Blue (HCOPTO000058) and Green (HCOPTO0059).







Datasheet:

HCOPTO0057_58_59_Datasheet.pdf

[ILYBTodd]

Hi Andrew,
I don't see a Forward Voltage value published in the datasheet. Everywhere I look Forward Voltage is what is used along with Supply Voltage to determine the Resistor Value of the Current Limiting Resistor. I've read where the Reverse Voltage is synonymous with Breakdown Voltage but only involved if applying positive voltage to the wrong terminal.

"The forward voltage is the voltage drop across the diode if the voltage at the anode is more positive than the voltage at the cathode (if you connect + to the anode).

You will be using this value to calculate the power dissipation of the diode and the voltage after the diode.

The reverse voltage is the voltage drop across the diode if the voltage at the cathode is more positive than the voltage at the anode (if you connect + to the cathode).

This is usually much higher than the forward voltage. As with forward voltage, a current will flow if the connected voltage exceeds this value. This is called a "breakdown". Common diodes are usually destroyed but with Z and Zener diodes this effect is used deliberately."

Can you help me out with this one please?

[andrew]

The manufacturer simply states the forward voltage as 5V @20mA for all three colours. However they will actually start conducting at forward voltages of 2.2V, 2.7V & 3V for the red, green, and blue LEDs respectively. The manufacturer doesn’t mention a current limiting resistor but the measured forward voltages imply they are just standard LEDs with a built-in current limiting resistor so that they operate with a current of 20mA at 5V.

If you’re planning on powering them at a higher voltage than ~5V you will of course need an additional current limiting resistor. However if that’s the case, and unless there is a good reason why you need to use these LEDs, then you’d be better off just using a standard LED with appropriate resistor as they are cheaper.

[ILYBTodd]

Thanks again Andrew. Always a pleasure working with you and Hobby Components.