Quick Answer: How Do I Know If I Have NPN Or PNP?

Can I use NPN instead of PNP?

Generally, the PNP transistor can replace NPN transistors in most electronic circuits, the only difference is the polarities of the voltages, and the directions of the current flow.

PNP transistors can also be used as switching devices and an example of a PNP transistor switch is shown below..

When would you use a transistor?

One of the most common uses for transistors in an electronic circuit is as simple switches. In short, a transistor conducts current across the collector-emitter path only when a voltage is applied to the base. When no base voltage is present, the switch is off. When base voltage is present, the switch is on.

Is PNP normally open?

PNP – (PNP transistor) NO – normally opened, that means there is no voltage on the output while the sensor is not actuated (see picture, PNP sensor output connector is no. 4).

Is sinking NPN or PNP?

PNP sensors are sometimes called “sourcing sensors” because they source positive power to the output. NPN sensors are sometime called “sinking sensors” because they sink ground to the output. The term “load” identifies the device the sensor powers.

What is transistor diagram?

Diagram ‘A’ shows an NPN transistor which is often used as a type of switch. A small current or voltage at the base allows a larger voltage to flow through the other two leads (from the collector to the emitter). The circuit shown in diagram B is based on an NPN transistor.

What is NPN and PNP output?

Answer. (1) NPN output type is used when connecting a load between power supply + and sensor output terminal. (2) PNP output type is used when connecting a load between sensor output terminal and power supply -.

What is PNP wiring?

PNP = Switched Positive. NPN = Switched Negative. “Switched” refers to which side of the controlled load (relay, small indicator, PLC input) is being switched electrically. Either the load is connected to Negative and the Positive is switched (PNP), or the load is connected to Positive and the Negative is switched (NPN …

Which is better NPN or PNP?

A NPN transistor has electrons as majority charge carriers whereas the PNP transistor has holes as majority charge carrier. The mobility of electrons is better than mobility of holes. … mobility of electrons is more than hole,so as a result npn transistor are faster than pnp that’s why they are preferred..

Which side of a transistor is the collector?

Transistors typically have one round side and one flat side. If the flat side is facing you, the Emitter leg is on the left, the Base leg is in the middle, and the Collector leg is on the right (note: some specialty transistors have different pin configurations than the TO-92 package described above).

What is the difference between NPN and PNP transistor?

PNP switches On by a low signal whereas NPN switches ON by a high signal. As we are aware that in PNP transistor, the P represents the polarity of the emitter terminal and N represents the polarity of the base terminal.

How NPN sensor is used as PNP?

Put a pull-down resistor on your input. Attach your PNP prox to your input. Invert the logic in the PLC. You will need to calculate what size and wattage resistor to use to satisfy the input’s requirements.

What is base emitter and collector?

The emitter-base junction injects a large amount of majority charge carrier into the base because it is heavily doped and moderate in size. Collector – The section which collects the major portion of the majority charge carrier supplied by the emitter is called a collector.

Which transistor is best for switching?

Best Transistors: BJTs#1 NPN – 2N3904. You can find most often NPN Transistors in low-side switch circuits. … #2 PNP – 2N3906. For high-side switch circuits, you need a PNP style BJT. … #3 Power – TIP120. … #4 N-Channel (Logic Level) – FQP30N06L.Apr 21, 2014

How do you decide between PNP and NPN?

PNP sensors produce a positive output to your industrial controls input, while NPN sensors produce a negative signal during an “on” state. If you learned to use sensors before gaining an understanding of transistors themselves, it would be easy to think that a PNP transistor is controlled with positive voltage.

How will you identify the base emitter and collector of a transistor?

Pin Identification of Transistors In plastic casing, one side of the transistor is Flat which is the front side and the pins are arranged serially. To identify the pins, keep the front flat side facing you and count the pins as one, two etc. In most NPN transistors it will be 1 (Collector), 2 (Base) and 3 ( Emitter ).

How do I know which transistor to use?

Transistor data is available from most suppliers, for example see Rapid Electronics.Choose the right type of transistor, NPN or PNP. … Find out the supply voltage(s) and load properties. … Work out the transistor properties required. … Work out a value for the base resistor R. … Check if you need a protection diode.

Is PNP or NPN more common?

PNP sensors tend to be more commonly used. Traditional relay type control circuit; Use with a programmable logic controller (PLC). … Less common nowadays are input cards that ‘source’, these were popular in Asia and require the NPN type of sensor in order to operate correctly.