Can I use dc to dc SSR like this http://www.ebay.com/itm/Solid-State-Relay-SSR-DC-DC-40A-3-32VDC-5-220VDC-40A-/170961637557?pt=LH_DefaultDomain_0&hash=item27ce1b90b5 to control 100w 36v high power led with arduino? I think that would be very easy way to control high power led, but does it really work?
Thanks for help!
Elias
Normally you would integrate a control signal into the constant-current supply circuitry
for such an LED and not need a separate switching device.
A simple MOSFET or BJT would be fine, an SSR is overkill for a low-voltage control
application like this unless there was a reason for an isolation barrier.
Thank you for your answer! Is it easier or cheaper to use mosfet to drive 100w led? And can you draw me a diagram and say all the parts I need to drive 100w led with mosfet. I think I can't only connect mosfet to arduino. I'm really grateful for your help! 
Thanks for a link! It looks very simple. So do I really need only one transistor and one resistor?