I just bought my first constant current devise for Led's and have a simple question to ask. The directions states to set up current for proper level I need to short circuit the output. That sounds dangerous, how do I do that the right way the first time? Vin will be a 24Vdc supply volt steady. Vout will be
21.0 Vdc. Thank you for help if you can.

 

I just bought my first constant current devise for Led's

Shorting the outputs does sound dangerous. It's a common practice to do just that, I need more information please,photo, or any information that came with with your purchase.thank you.

 

You can also try a resistor across the output. Select the resistance value to draw more current than you want at the voltage you calculate the LEDs to require. This method is safe, cheap, and easy.