I am making a circuit using a 4 pin hall sensor with arduino. It turns out that the hall sensor outputs a negative voltage as output, which arduino cannot read, so I will need a PNP transistor, I don't have one but I have a bunch of NPN (BC547) laying around. Is there any way I can make a PNP transistor or add circuitry to make the NPN into PNP? Thanks in advance. For more info about the hall sensor, the first pin is +ve second is Normally open third is Normally closed and fourth is -ve Schematic

Turns out that I have a pnp transistor with my Snap Circuits kit. I cracked it open, soldered some wires and now, it looks like this image Take a look at my Schematic above and tell if I need another resistor or somethin

  • \$\begingroup\$ I also want to make a circuit with arduino and a ir sensor which also turns out that it outputs negative voltage. So I need this very badly \$\endgroup\$
    – Bheeshma
    Apr 7, 2021 at 3:30
  • \$\begingroup\$ In principle, you can do it. Show us the circuit. \$\endgroup\$ Apr 7, 2021 at 3:33
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    \$\begingroup\$ Wrong question - you want to convert your signal to something useful for the Arduino. Converting pno into npn is not the issue. \$\endgroup\$
    – Kartman
    Apr 7, 2021 at 3:38
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    \$\begingroup\$ @Bheeshma: The schematic is private on your Google drive - no one else can see it. \$\endgroup\$
    – JRE
    Apr 7, 2021 at 14:07
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    \$\begingroup\$ @Bheeshma - Please stop using Google Drive links for your schematics. (a) As already commented, you are providing private links, which means we cannot see your schematics. (b) When those links become unavailable in future, then the question becomes useless. || Therefore please use the site's built-in image upload capability. Click edit then hit Ctrl+G (on a PC) (or click the "mountains" icon above the edit box) and follow the on-screen instructions to upload the image(s). Images need scaling to be no larger than 2MB before uploading. Thanks. \$\endgroup\$
    – SamGibson
    Apr 7, 2021 at 15:07

2 Answers 2


No. You can't change an npn transistor into a pnp transistor.

  • 2
    \$\begingroup\$ Well a Sziklai pair sort-of does but I don't think that mentioning that will help the querant. \$\endgroup\$
    – Jasen
    Apr 7, 2021 at 5:16

NPN transistor can't be converted into PNP transistor. This question is already discussed here. How can I convert a PNP to NPN transistor?


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