# NPN 2N2222 transistor component as switch circuit



## Tessie (Aug 6, 2021)

I have watched a video on the internet. And I do my project following this and have trouble using a PNP 2n2222 transistor*.* It normally allows current to flow except when you supply the base with a little more current than the collector? I wasn’t able to get the PNP to work in a reliable way. I did connect the base to the ground and I’m pretty sure it melted?! Could anyone explain why that happens?


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## Lucerust (Mar 11, 2012)

Tessie said:


> I have watched a video on the internet. And I do my project following this and have trouble using a PNP 2n2222 transistor*.* It normally allows current to flow except when you supply the base with a little more current than the collector? I wasn’t able to get the PNP to work in a reliable way. I did connect the base to the ground and I’m pretty sure it melted?! Could anyone explain why that happens?


Hi, can you provide a cct diagram of how you are connecting the transistor?


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## Tessie (Aug 6, 2021)

Hi, this is the diagram. Can it work?


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## Lucerust (Mar 11, 2012)

Hi Tessie, the 2N2222 is an NPN transistor. You have drawn it correctly in your diagram. If the cathode of the LED is connected to 0 volts (ground) as shown in the diagram, and the collector of the transistor is connected to +5 volts or greater (the upwards facing green arrow head), then it should be perfectly safe to connect the base to ground. To light up the LED, try connecting the base to the collector. Connected like this, the transistor is operating as what is called an emitter-follower. This just means that the voltage on the emitter will follow the voltage on the base (less 0.6 volts).
I suggest you double-check the pin-outs on the transistor and try again (maybe with a new transistor). If anything's unclear, feel free to ask more.


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## Lucerust (Mar 11, 2012)

This should be the pin-outs for the 2n2222


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## Tessie (Aug 6, 2021)

Lucerust said:


> Hi Tessie, the 2N2222 is an NPN transistor. You have drawn it correctly in your diagram. If the cathode of the LED is connected to 0 volts (ground) as shown in the diagram, and the collector of the transistor is connected to +5 volts or greater (the upwards facing green arrow head), then it should be perfectly safe to connect the base to ground. To light up the LED, try connecting the base to the collector. Connected like this, the transistor is operating as what is called an emitter-follower. This just means that the voltage on the emitter will follow the voltage on the base (less 0.6 volts).
> I suggest you double-check the pin-outs on the transistor and try again (maybe with a new transistor). If anything's unclear, feel free to ask more.


Hi Lucerust,
Thank you for your kind help.
I will retry this with your suggestion.
Have a good day!

Yours Sincerely,
Tessie


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## Drilkens (May 3, 2021)

Have you solved your question? I can draw a wiring diagram for you, if it's still relevant.


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