As small question about a relay board.
I have a couple of those cheap aliexpress relay boards I need to use in a project. I looked for hours online in various tutorials, but I cannot seem to find a definitive answer. When testing (because there is no manual offcourse) I found that pulling an input pin of the board to ground activates the relay. Easy enough. But then it has 2 ways of powering the board, I can either power it by using the GND and VCC pins right next to the input pins, or I can power it externally by removing the jumper and feeding 5V and GND into the other header. This header has [GND * VCC- * JD-VCC] and by default has a jumper between VCC an JD-VCC.
For what I understand, I need to remove the jumper, supply JD-VCC and GND from an external PSU with 5V, and then hook up 3.3V from the rpi to the VCC pin? Is that correct? This is because the relays pull too much current from the GPIO pins, correct?
If so, am I mistaken that in that case I am trying to trigger a 5V relay with a 3.3V signal from the rpi? It seems to work fine using the 3.3V VCC method, but I am not entirly sure I am doing the right thing here. I'd love to have some confirmation from someone who actually knows what he is doing,I don't need any more blown RPi's because of incompetence :-)
I have added a picture for clarification, I hope this helps?