Hi Guys! I welcome you on board. In this post today, we’ll discuss KSC1845 NPN Transistor. We will also discuss KSC1845 Datasheet, Pinout, Power Ratings, Equivalents & Applications. As this is an NPN transistor, electrons play a major role in conductivity inside the transistor. It is different than PNP transistors where holes are the major charge carriers. KSC1845 is mainly used for switching and amplification purposes.
NPN transistor carries 3 terminal, known as:
If the voltage at the base terminal is above 0.7V, it will forward bias this NPN transistor and current will flow from collector to emitter pin. If the base voltage is less than 0.7V, it remains reverse biased.
I suggest you buckle up as I’ll discuss KSC1845 NPN Transistor in detail.
Let’s get started.
KSC1845 NPN Transistor
The KSC1845 is a bipolar junction transistor that falls under the NPN transistor family.
It is made of silicon semiconductor material and comes in a TO-92 package.
The NPN transistors carry two junctions known as emitter-base junction and collector-base junction.
When the emitter-base junction is forward biased and collector-base junction reverse biased, then the transistor starts to conduct with enough current available at the base pin.
We can make the emitter-base junction forward biased when a negative voltage is applied at the emitter side and positive voltage is applied at the base side.
KSC1845 contains three layers where one p-doped layer sits between two n-doped layers. The p-doped layer represents the base terminal while the other two n-doped layers represent connector and emitter respectively.
This component comes with three terminals called the base, collector, and emitter. The emitter side emits the electron into the base side while the collector side collects the electrons coming from the base side.
The bipolar junction transistors come in two types i.e. NPN transistors and PNP transistors. As the name suggests, both holes and electrons play a role to carry out the conductivity process inside the transistor.
But in the case of PNP transistors, holes are the major carriers, and in the case of NPN transistors electrons are the major carriers.
These bipolar components are called current-controlled devices in opposed to MOSFETs that are considered voltage-controlled devices and carry terminals like a drain, source, and gate.
Know that the mobility of electrons is better than the mobility of holes, this is why NPN transistors are preferred over PNP transistors for a range of applications.
Before you incorporate this device into your electrical project, it’s wise to go through the KSC1845 datasheet that details the main characteristics of the device. Click the link below to download the KSC1845 datasheet.
The following figure shows the KSC1845 pinout.
This component contains three terminals named:
All these terminals are used for the external connection with the electronic circuit. These terminals differ in terms of size and doping concentration. The base side is lightly doped and the emitter side is highly doped while the collector side is moderately doped.
The collector side dissipates more energy because it is bigger in size compared to other terminals. The large surface area of the collector side ensures more heat dissipation.
KSC1845 Working Principle
The base side is the main region that initiates the transistor action. When voltage is applied at the base terminal, it will bias the device and as a result, current starts flowing from collector to emitter side.
These bipolar devices are not symmetrical in nature. Which means if we exchange the emitter and collector sides then these terminals will stop working in forward active region and start working in reverse active mode.
The different doping concentrations of these terminals ensure the lack of symmetry.
KSC1845 Power Ratings
The following table represents the KSC1845 power ratings.
Absolute Maximum Ratings of KSC1845
Operating and storage junction
-55 to 150C
When using this device, make sure these ratings don’t exceed the absolute maximum ratings else they can damage the device.
Plus, if these ratings are applied more than the required time, they can affect the device reliability.
The collector-current is 0.05A which shows the amount of load this device can support.
The power dissipation is 0.5W which represents the amount of energy released during the working of this component.
The current gain is 200 which shows the amount of current this device can amplify.
The collector-base voltage is 120V and the collector-emitter voltage is 120V. The emitter-base voltage is 5V represents the voltage required to bias this component.
The following are the KSC1845 equivalents.
Before applying alternatives into your projects, double-check the pinout of these alternatives as the pinout of KSC1845 might differ from the pinout of the equivalents.
The KSA992 is a complementary PNP transistor to the KSC1845.
The following are the KSC1845 applications.
Incorporated in modern electronic circuits.
Used in high-frequency power transform.
Used in electronic Ballasts.
Used in voltage regulator circuits.
Used in a common power amplifier.
Used in Bistable and Astable multivibrators circuit.
Used in energy-saving lights.
Employed to support loads under 0.05A.
Used in the high switching power supply.
KSC1845 Physical Dimensions
The following diagram shows the KSC1845 physical dimensions.
The KSC1845 physical dimensions help you evaluate the space required for this component in the electrical project.
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