Wire a push-button switch to close a circuit instead of open it?
I bought several pushbutton switches from Radioshack, and I just discovered that pressing the button actually breaks the connection between the two pins, rather than closing the connection.
Is there some simple combination of diodes that I could use with such a switch to make it close a circuit, instead of open it? It seems like it should be possible, but I can't figure it out.
- wingstwoLv 71 decade agoBest Answer
There are two basic single throw switch circuits: normally open and normally closed. You need a NC switch.
You bought a NO switch, when you activate it, it closes. Are all the switches the same, or was it an assortment. If not the same, likely one is NC and will work. Many switches have multiple contacts, so they do NO and NC at the same time.
Maybe possible to reverse circuit to work with diodes, but why bother? Switches are not expensive.
3 diodes is not a transistor, it's 3 diodes. Build your 3 diode transistor some time, and you will find it doesn't work as a transistor! The models they use to teach about semiconductors have some valid characteristics, but are generally grossly flawed. You need to know when each model is valid.
- Anonymous1 decade ago
Simple push buttons are provided in 2 options
Ones like those you have which open when pushed these are called normnally closed contacts
The second closes when operated these are called normally open contacts
So 2 options normally open and normally closed
Normal position is when there is no external force on the button
So go back to Radioshack and buy some normally open pushbuttons is the simplest option
You will have some spare buttons of each type for future projects
- Poor oneLv 61 decade ago
You could use a relay or transistor but either would seem to be over complicating the whole thing for the sake of going back to radio shack and buying a push button with NORMALLY OPEN contact. They will probably exchange what you already bought and these things are not expensive.
I cannot think how diodes would help. I certainly forgot that.
- Anonymous1 decade ago
I am going to answer the question asked, not suggest that jsprplc2006 go back and get another switch...he asked if there's a way to use diodes to solve his problem...that's IT.
so, here goes...
You could fake an open collector PNP transistor with three diodes and a few resistors. In case you don't remember, a transistor is three diodes connected together. [q.v: a PNP transistor is three diodes with a common cathode]
Wire the NC switch/button to bias the PNP OFF when the switch is not activated [switch closed] so the collector conducts when the switch is activated [switch open].
how does everybody forgot that a transistor is three diodes?
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- Anonymous4 years ago
wire pushbutton switch close circuit open
- DavidLv 44 years ago
Push buttons perform the same function as a switch. The circuit, obviously, functions only as long as the button is depressed. "connect it directly to battery & buzzer" connect what? seems like it would be on all the time if you did this.
- billrussell42Lv 71 decade ago
in a SPECIFIC application, ie, a specific circuit, you might be able to do something with a transistor or two, but that would depend on the circuit.
- LaurenceLv 41 decade ago