What is an SL100 Transistor : Working & Its Applications

In integrated circuits, transistors are basic building blocks. At present in every electronic device or gadget, we can notice transistors like BJTs. These transistors use both the charge carriers like electrons and holes. BJTs are classified into two types like PNP & NPN. This article discusses the most common type of transistor namely the SL100 transistor.

What is an SL100 Transistor?

The transistor-like SL100 is a medium, general-purpose power NPN transistor. So this transistor is used in a wide range of electronic applications like switching, logic gates design, reproduction of sound, amplification, signal processing & radio transmission.

SL100 Transistor
SL100 Transistor

However, it is normally used as a switch within the configuration of CE (Common Emitter). This transistor is turned ON once fixed DC voltage is applied (biased) and if there is a signal on its base terminal & it is turned OFF completely in the nonexistence of the base signal.

Based on the biasing of a transistor & different circuits can be connected to it, so that the transistor works either like a switch or an amplifier. When the transistor works as an amplifier, it can transmit or obtain radio signals to achieve analog mathematical calculations or produce signals in between other functions.

Similarly, when the transistor works like a switch, it controls different loads like motor, light, etc, and performs different mathematical & digital logic operations.

SL100 Transistor Pin Configuration

In the transistor, the first letter signifies the material whereas the second letter signifies the device type. So in the Sl100 transistor, the first letter ‘S’ is the Silicon material whereas the second letter ‘L’ is a device with High Power & Frequency.

SL100 Transistor Pin Configuration
SL100 Transistor Pin Configuration

The pin diagram of the SL100 transistor is shown below. This transistor includes three pins namely base, emitter, and collector.

  • The emitter terminal is a protruding edge within the transistor. This terminal supplies the majority of charge carriers.
  • The base terminal is nearby to the emitter terminal and is located in the middle section.
  • The collector terminal collects the majority of charge carriers which are supplied through the emitter terminal.

Features & Specifications

The features and specifications of the SL100 transistor include the following.

  • It is an NPN transistor with medium power
  • Storage & Operating Temperature range from-65℃ – 200℃
  • Collector-Emitter (CE) voltage is 50V
  • Output Capacitance is 20pf
  • Collector Base (CB) voltage is 60V
  • DC Current gain is 100 to 300 hfe
  • Emitter Base (EB) voltage is 5.0V
  • The saturation voltage from Base to Emitter is 1.3V
  • Collector Current is 0.5A
  • The saturation voltage from Collector to Emitter is 0.6V
  • Designator Type is SL100
  • Dissipation of Collector Power (Max) is 0.8 W
  • Transistor Material is Si
  • Package is TO-39
  • NPN Polarity
  • Ruggedness is High
  • Easy drive requirements
  • The operating area is high safe
  • For less distortion balancing designs
  • Easy to handle & carry

Equivalent Transistors

Equivalent SL100 transistors mainly include P2N2369, MZT3055, P2N2907A, P2N2369A, PN100, 2CF2325, PN200, BC548B, 2N3055HV, 2N23867, 2N6371H, BD237S, A1941, BD675BPL, BU908F, BF422BPL, 2N3904 & BC301.

How to use SL100 Transistor?

The circuit diagram of an SL100 Transistor namely continuity tester is shown below. This circuit can be built with some basic components by beginners easily. In this circuit, the SL100 NPN transistor plays a key role. This simple circuit generates visual light from LED & audio sound from the buzzer once the stability is there at the probs.

Here, the circuit’s closed continuity can be detected through the characteristics of the NPN transistor. So, a 5 volt supply is provided to the collector terminal of this transistor throughout the LED & the buzzer. The emitter terminal of the transistor is connected directly to the negative terminal of the battery.

SL100 Transistor Circuit Diagram
SL100 Transistor Circuit Diagram

The base terminal of the transistor works like the probe once the least bias takes place at the base terminal of the transistor and it will operate as a closed switch after that the buzzer & LED will provide output throughout the way we can obtain recognize the stability in between the probs.

An electronic device like a continuity tester is used to test the equipment for determining if the electrical element can be found among two pins.

This tester includes two probes when the two probes get in touch with each other then shows the audio & visual indications. If the circuit has visual and audio indications then the circuit will have good continuity.

If you desire to ensure the circuit’s continuity, then first you have to get the two probes from the above circuit. One probe must keep at the terminal of the circuit whereas the other one has to touch to check the continuity. So if the continuity of the circuit is good then the circuit gives indications of LED and beep sound.

Where to use Sl100/Applications

The applications of the SL100 transistor include the following.

  • Switching
  • Logic Gates Manufacture
  • Reproduction of Sound
  • Amplification
  • Processing of Signal
  • Radio Transmission
  • This transistor is used to make automated circuits like alarm circuits by detecting rain, an indication of water level, etc.
  • Some other application circuits like Automatic Street lights, beepers, solar chargers, emergency lights, gas sensors, automatic voltage stabilizers, etc.

Difference between BC107 & SL100 Transistors

The difference between BC107 & SL100 transistors includes the following.

In BC107 transistor, BC stands for Buried Channel & the 107 is the version of the product that specifies how many types of materials are used to manufacture this transistor. The medium power NPN transistor like SL100 is used as a switch within the CE configuration. This kind of transistor’s terminal needs a stable DC voltage to manage within the preferred area of its characteristics, so this is called biasing.




Number of Pins

Three Three
Polarity NPN



To39 To18
CE Voltage 50V



Emitter, Base & Collector Emitter, Base & Collector

Complete Power Dissipation



Gain Below 100dB

Below 30dB


125 to 500 100 to 300
The capacitance of Operating and Storage Junction -65 – 200°C

-65 – 200°C


Switch and General Purpose Amplifier

Switch and Power Amplifier

Thus, this is all about an overview of the SL100 transistor. It is extremely economical & easily available in the marketplace, so it is used in a wide range of applications. An SL100 transistor is enough to design a simple tester circuit to provide audio & visual outputs once the stability is there at the probes. Here is a question for you, what are the different types of transistors available in the market?