I'm new to the electronics world and am having some trouble wrapping my head around something. I have one of these missile switches and I can't get it to work. I think I've tried every possible method of wiring, but can't for the life of me figure out what I am doing wrong.
I've gone from trying to read the state of the switch to simply using it to toggle a led on/off and still I'm not managing. The comments on the product page do give some instructions from other users, since sparkfun wasn't willing to, but as said it doesn't work for me. I'm obviously doing something wrong. The 12V is supposed to be the power input to the switch, but what's the role of the LED pin? How do I wire from the ground pin?
I would be very thankful to anyone who could draw out a simple breadboard example (I find those easy to follow, technical drawings less so) how I could toggle a led using this switch.
I would try Vcc to "12v", load to "20A" and tab to gnd.
To use on an Arduino, I would have "12v" connected to 5v, "20A" connected to a 10k R to gnd and the input pin connected to the junction of the R and "20A". The tab should then connect to gnd.
The switch connects the "12v" contact to the "20A" contact as well as one end of the LED. The tab is the gnd end of the LED.
I have a very similar one I got from Radio Shack. It has 3 tabs as well, but the physical arrangement is different. But I suspect that it works the same way. One tab is "Ground" (or actually the cathode of the LED, pin 3 in the sketch). One tab is "Power" (pin 2 in the sketch) and the third tab is the other side of the switch from "Power" (pin 1 in the sketch). The third tab is connected to the anode of the LED. When the switch is ON, "Power" and anode are connected.
Use your diode check function on your DMM. In the OFF position, you should be able to find which two tabs are for the LED (polarity sensitive).
Use your diode check function on your DMM. In the OFF position, you should be able to find which two tabs are for the LED (polarity sensitive).
Some LEDs will not be forward biased by a DVM.
If this is the case with the OPs DVM, they can use a 9 volt battery and a series 220 ohm resistor to identify the terminals of the LED. They may have to reverse the battery to make th LED light.
LarryD:
Some LEDs will not be forward biased by a DVM.
If this is the case with the OPs DVM, they can use a 9 volt battery and a series 220 ohm resistor to identify the terminals of the LED. They may have to reverse the battery to make th LED light.
AFAIK, LEDs don't like a reverse voltage of more than ~5volt.
Explanation is ok, but I would use a 5volt source to test the LED.
This switch seems to have two terminals, not three or four..
That means the internal LED must be wired between those two terminals (maybe with a bridge rectifier).
Then this switch can only be used for a load that's several times the current of the internal LED.
This switch can't switch (off) another single LED.
Leo..
Reverse basing a LED will put it into its zerner region.
For the fraction of a second used in testing, no damage will occur.
9v and a 220 ohm resistor is just fine for testing, and is easy and convenient.
@Wawa:
Were you talking about TS's switch ?
The one he linked to does have 3 terminals:
One next to the word "OFF", one next to "12V", and the last one next to "20A"
