Как из pnp датчика сделать npn
Вариант №1: воспользоваться специальным преобразователем, например устройством согласования сигналов УСМ, которое представлено у нас в ассортименте, или аналогичным.
Вариант №2: если вы хотя бы минимально дружите с паяльником, сделать преобразователь самому.
Если в наличии есть датчик с PNP выходом, а нужен NPN — собираем вот такую схему:
Транзистор Q1 — любой подходящий NPN, например 2SC495, BC445, BD237.
Если же в наличии имеется датчик с NPN выходом, а нужен PNP — такую схему:
Транзистор Q1 — любой подходящий PNP, например 2N5401, КТ502Д.
How to convert NPN transistor to PNP transistor? [duplicate]
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
How to Convert NPN to PNP transistor?
I’m creating a water level indicator so I can turn on a pump when the water level gets too low. I have NPN transistors, but I would like the transistor to act as a switch that closes when the water level drops below a certain height. The NPN transistor I used for the experiment seems to do the opposite (close the switch when the water level is high enough), so I figured I need to use a PNP transistor instead. However, after following this SO suggestion and flipping the connection to the battery terminal as well as the LED, the LED did not turn on as expected when the water level gets too low. I would appreciate your advice. The circuit below lit the LED when the water level closed the circuit. How do I get the LED to turn on when the circuit is open? simulate this circuit – Schematic created using CircuitLab
asked Jan 3, 2020 at 23:07
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How can I convert a PNP to NPN transistor?
I have a circuit which requires a PNP transistor. I only have an NPN transistor. Is there a way to convert one to the other given that they have the same characteristics (apart from the npn/pnp part?) And for others after me. can the reverse also be done? e.g. how does one convert a PNP transistor to its NPN equivalent?
asked Dec 16, 2012 at 10:44
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\$\begingroup\$ It may be possible to use one for the other in a given circuit with a small design change, but what you’re asking is not possible, there is no conversion to make a NPN into a PNP. \$\endgroup\$
Dec 16, 2012 at 11:09
\$\begingroup\$ Could you post the schematics of the circuit you’re dealing with? Or at least, what’s the load that is supposed to be switched be the PNP transistor? \$\endgroup\$
Dec 16, 2012 at 11:15
\$\begingroup\$ So get some PNP already. Transistors are cheap and available. Get a handful of 2N4401 (NPN) and 2N4403 (PNP). These will be good for a lot of hobby projects and are quite cheap if you buy 100 or so at a time. That should last a while. \$\endgroup\$
Dec 16, 2012 at 14:36
\$\begingroup\$ What you are wanting to do is not possible — BUT as others have said, if you provide the cct diagram people can help with ways to use an NPN transistor BUT otherwise you are wasting your time and that of other people. \$\endgroup\$
Dec 16, 2012 at 14:48
\$\begingroup\$ @RussellMcMahon My actual question was really specific so I asked it in a more general way first because this answer might help more people than just me. I’ll do a follow up question which is much more specific \$\endgroup\$
Dec 16, 2012 at 17:02
3 Answers 3
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If it’s the only type of transistor in the circuit, the translation is straightforward; build the circuit as designed, reverse the power connections and any other polarised components (diodes, electrolytic caps).
If you need one PNP in a mostly NPN circuit, there is no general solution.
There may be solutions, depending on the configuration of the PNP stage.
For example, if the PNP transistor was being used as an emitter follower, and you have the headroom, you may be able to use an NPN in common emitter, with Rc=Re so that its gain is (approx) 1.
If the PNP transistor was in a complementary power output stage but you can only find low power PNP transistors, I remember seeing an arrangement using a PNP driver transistor and an NPN power transistor to «replace» the non-existent PNP power transistor. Peter Walker did this around 1970 for the Quad 303 power amp (I believe 3 transistors were involved) when there was no PNP version of the famous 2N3055.
And there may be other such substitutions.