I've got this single-channel relay for my Raspberry Pi. The relay has 6 pins instead of the usual 3, more over out of the box there was a jumper connecting 2nd and 3rd pin (I'm counting pins from top to bottom starting with 1). This is my first ever interaction with both relay and a Raspberry Pi. Why is there a jumper on the relay? And how to use it?
I've hooked up 1st pin to 5V PWR GPIO on Raspberry Pi, 4th pin to GPIO4 and 6th pin to GND. In given configuration LED on relay board lights up whenever I send GPIO.LOW output on GPIO4 but relay isn't clicking.