CUrrent to drive relay

Other Hardware General Electronics
1

I can't get any search to work so I scanned for the same question but saw nothing obvious in the titles. Search near top right just takes me to the internet.

I am trying to drive relays. The board, from another company, was identified as a Creatron RELAE-810810. It conatins relays type: SRD-05VDC-SL-C which is a "sensitive" 5V relay that takes 71mA to switch. The board has an optocoupler type: DP 817C 1618 which has a gain of 200-400%. At 200% that means it requires 35.5mA which is well above the rated 20mA output for the Arduino. What am I missing?

Thanks

Richard

2

Usually relay modules has not only an optocoupler but an additional transistor. So 5 mA is enough to switch a relay.

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