I think you're getting enough current for the relay to start to engage (hence the faint click) but not enough to flip all the way over. According to the relay spec you linked, you need approx 89 mA for the relay to switch on completely, which is approx what you get when you ground it. Your single transistor with 40 mA is only providing about half of that.thogue wrote:Well anyways, the transistors work to control LEDs that require 2-3ma (I measured ma, via the multimeter). Also the relay clicks on if I simply "ground" the pin that should be going to the collector. If I attempt to "switch" the relay via gpio I hear VERY faint clicks, but the relay does not do its thing. When I measured current draw of the transistor with the relay hooked up to it, (and switched on via GPIO, I read about 40~mA, If I read the current draw of the relay connected directly to ground (causing it to switch on) the draw is 84~mA.
[Edit: I wrote this before seeing preceding post.]thogue wrote:Actually I tried all 3 transistors. I also have tried using two transistors as that seemed like a logical move when I saw I was seeing half the current draw then what was needed.... But it didn't do the trick and quickly made question my understanding.
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