I have the FEZ Ultimate KIt (awesome BTW), and also just bought a Relay16 board. I’m wondering what the total current draw is for the board if I had to hold all relays powered up. I ask because I’m thinking of cascading 2 of these boards and need to know how much power is needed at max load. Thanks.
Your load puts stress on the relay itself and not on FEZ. You can have 4 of these and it wouldn’t change anything from the micro point of view.
I think he wants to know how much current the coil of those relais draw when activated. I used relais that draw 20mA, but also ones that draw 150mA. So it certainly something you need to keep in mind when calculating the total power consumption of a system.
@ Wouter, you’re correct. I stopped being lazy and found the relay’s spec sheet online (http://panasonic-denko.co.jp/ac/e/control/search_num/index.jsp?c=detail&part_no=AJQ1341F&table_name=POWER_RELAY_DATA). It says 100ma @ 5v. So that’s 0.5w power consumption. Not sure why the sheet references 5v when it’s a 12v relay. If I’m reading the spec sheet correctly, it means each relay consumes 0.5w, which at 12v is 41.6ma. All 16 relays being held closed should then consume 666ma. So a 12v 1A power supply should be able to easily power the relay board.