View Full Version : How to tell pin 1 on 4-pin push-button?

Tom F
05-17-2006, 10:24 PM
Can someone tell me how to tell pin 1 on 4-pin push-button?

I haven't seen anything in WAM that explains.


Tom F
05-17-2006, 10:27 PM
Of course I can always do a continuity test, but I'm wondering if there's a standard. There IS a semi-circle on the bottom of the device, with (as all semi-circles have!) a flat edge. Is that a standard indicator?

Tom F
05-17-2006, 10:31 PM
Ohhhh! I just was re-inserting the push-button on the breadboard after my last eye-squinting examination of the bottom and by seridipity discovered that it only fits across the gap on the breadboard in one orientation!

I didn't notice that the first time I inserted it.

So my question is answered!

05-17-2006, 11:50 PM
I thought that with those type of buttons if you always used pins on opposite corners you would be okay no matter how you plugged it into the breadboard.

Chris Savage
05-18-2006, 01:24 AM
You could look at it that way...If you place these types of switches sideways so that it's slightly longer from left to right, they're usually setup so that the top two pins are joined and the bottom two are joined. Here is a snap from a recent PCB using any of the three similar buttons that Parallax carries. As you can see, the bottom two go to ground, and the top two go to input lines.

Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)