I have been pulling my hair out trying to figure out the pin out for the Smallbear/macron vactrols. I have a pair of 5ct3 work alikes for a compressor and I can't for the life of me figure out which leg of the LED side is the anode and which is the cathode.
The dot is on the opposite side of the letter (a "c" in this case) and is on the same side as the short leg. Normally I would just stick the long leg in the square PD and be done with it, but these things are screwy.
And I am also too breadboard incompetent to put a LED in series to figure it out that way.
Send help. Please!
You should be able to use the diode setting on a multimeter to determine the polarity. On the LED side of the vactrol, place the black probe on one lead, the red on the other. If you get a Vf reading no connect, you've got the orientation backward; if you get a reading in line with LED read outs, the anode is connected to red and cathode to black.
Quote from: benny_profane on March 07, 2020, 09:34:48 PM
You should be able to use the diode setting on a multimeter to determine the polarity. On the LED side of the vactrol, place the black probe on one lead, the red on the other. If you get a Vf reading no connect, you've got the orientation backward; if you get a reading in line with LED read outs, the anode is connected to red and cathode to black.
My multimeter reads the same in both configurations. In diode measuring setting, which works on normal diodes but not LED's I guess
That's really strange. What reading are you getting? Are you sure you're working with the LED side and not the LDR side?
Quote from: benny_profane on March 07, 2020, 10:37:24 PM
That's really strange. What reading are you getting? Are you sure you're working with the LED side and not the LDR side?
Yes, as long as the spot is on the LED side of the vactrol.
On the 5c4 works likes the spot indicates the positive leg of the LED, evidently. I actually made an LED light up on my breadboard..... I'm a real DIY person now
I've become lazy. I use my Peak Atlas DCA55 for detecting anode/kathode, these days.