On the common Arduino-compatible relay modules, like this one on the auction site, 221482044195, how much 5V do you sink per channel when they are turned on? Seems like full specs are a little hard to find. Thanks in advance
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3 ma relay off
80 ma relay on
per one relay unit...
cjack posted:3 ma relay off
80 ma relay on
per one relay unit...
Yikes! That is 400 mW per relay.
I assume that is the total 5V supply current including the coil. Do you know what the current through the data line alone is?
Thanks in advance for all your help.
Wouldn't that be the 3 ma?
There are variants, but from your pic it appears to be the style where the "data" input goes thru a 1k resistor in series with an LED and opto-isolator LED. In my experience, 1 mA always trips the relay as the NPN on the output of the opto-isolator provides the 80mA coil current. But as you know opto-isolators are wide-ranging in CTR. I've been able to trip these with a few 100 uA - the input LED is very dim in such cases.
Oh sorry. I get the question now. When I short the IN directly to GND, the IN draws about 7 ma. I did not try any resistance in series with the IN to GND.
OK, so we are in the magnitude of a couple mA to the data input, and about 80 to supply the coil. Working on a "cheapie" project, and am more concerned about sensitivity to "leakage" currents than power consumption at this point. From your description, the input is a couple LED drops in series with 1Kohm, although CJack's unit might draw a little more.
I will order a few of these and see how I make out. Thanks to CJack and Stan2004 for all your help!
