Well I am a beginner in electronics. So, I have some 4 pin tactile switches and I am confused about placing them in the breadboard. Here is the poorly drawn photo of the two ways of placing by me. Forgive me for such shitty kind of photo. enter image description here

So,when I place the switch in the way (A)(follow the image) , the switch is so loose . I am adding another image. enter image description here

So, In A type, When I connect one upper end to +ve of a battery , direct flow of current is seen on one lower end (IMAGE 2) but the other lower end doesn't flow current , only if I push the switch and hold it, the other end also flows current.

now, go to type B. here, I am placing the tact switch horizontally (B), and connect any of the 2 left side pins to the +ve of battery , the other left side pin also gets charged , because of the vertical hole lines (vertical with respect to the images) of breadboard. so , if I connect that, the right side two ends both gets charged . even if I push the switch, still the right end pins get charged. I've seen many comples circuit tutorials on youtube where they used a tact switch and placed it in type (B) , and they pushed the switch once but did not hold it, and the current started to flow. they pushed the switch again , and the circuit broke , How can I properly use a tact switch as a proper switch by placing it in type (B) and I want to use it a a proper on-off switch . Please help. If there are mistakes in my description , then you are welcome to re-edit it or comment. Please do help. I know that I dont know much of the electronics terms and I just started everything as beginner. Please help.

  • \$\begingroup\$ Get a multimeter and test the pins unless you can distinguish this from the datasheet theres no way to know which pins are connected. Once you've found this out you can then either use both side or just the one set of pins. \$\endgroup\$
    – Dean
    May 25, 2013 at 14:10
  • \$\begingroup\$ I tested the pins by multimeter and found out that when its placed horizontally (type B) and one of the leftside pins are connected to +ve of battery (9V) {note that the -ve of battery isn't connected to anything, so that I can plug the -ve of battery to the COM wire of multimeter and the red wire of it to the pin I want to test} , I see that both of the two pins on the right side are charged and even if the switch is pressed, it doesn't change. So, I am not getting a proper SWITCH when placed in B type \$\endgroup\$ May 25, 2013 at 14:20
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    \$\begingroup\$ +1 for an entertaining set of illustrations! I prefer these over the pure wall-of-text descriptions some people post. They're not photos, though :-) \$\endgroup\$ May 25, 2013 at 15:56
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    \$\begingroup\$ Give the pins a squeeze with a pair of needle nosed pliers to straighten them out. They will then sit much easier in the breadboard. \$\endgroup\$
    – Hoppo
    May 25, 2013 at 22:41

3 Answers 3


It looks like you have one of these:

Push-button with annotation

All of the ones I've used have been SPST switches with the 2 legs that point toward each other connected together in electrically identical pairs; the switching is done from pair to pair.

In your B diagram, the switch is just acting as a jumper between the pads, as you noticed.
In A, the lower right pin should always at +Ve; the 2 left pins would be at +Ve when the button is pushed, and floating otherwise.

These switches were designed for printed circuit boards, not solderless breadboards, but they'll work OK if you straighten the pins a little bit.


Perhaps this drawing will help. enter image description here

As you can see on the right hand part of the part of the diagram pins 1 and 2 are connected together. Pins 3 and 4 are connected together and the switch action is between these pairs of pins.

Using a multimeter set to low ohms (resistance) you should find that the two sets of pins that are short circuit. These correspond to pins (1,2) and (3,4) in the diagram.

To get a switch action you need to connect one side of your circuit to pins 1,2 and the other side to pins 3,4. Of course you do not have to connect both pins on each side of the switch. It will work by connecting 1 and 3 or 2 and 3 etc.

a data sheet can be found here http://www.omron.com/ecb/products/pdf/en-b3s.pdf

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    \$\begingroup\$ A link to the datasheet where you found the image would make the answer complete. Good find. \$\endgroup\$
    – jippie
    May 25, 2013 at 15:42
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    \$\begingroup\$ @ jippie Couldn't find exactly the same one but the pdf contains all the same information so +1 for suggestion \$\endgroup\$ May 26, 2013 at 8:22

One suggestion is to get an Omron B3F-6000 series (I ordered the Omron B3F-6022, Mouser has 'em) or equivalent switch instead of the four-legged types you are currently using. As the drawing below indicates -- these switches have two pins, on a 5mm spacing, which makes them almost ideal for breadboarding. Simply clip them from the tape with a pair of side-cutters and stick them in as you would any other two-legged component.

B3F-6022 drawings from the Omron B3F series datasheet


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