The 2N3055 is a bipolar transistor used in power amplification and switching applications. The 2N3055 is an NPN type bipolar transistor commonly used in low to medium power electronic circuits.

2N3055 is an NPN type transistor. Its function is similar to that of a pass-type transistor. It consists of three terminals, namely the emitter, base and collector. It is a current adjustment device that adjusts the large current on the other two terminals by adjusting the small current on the base terminal, thereby achieving the purpose of adjusting the large current on the other two terminals.

In this type of transistor, the movement of charge currents such as holes and electrons is achieved by conducting electricity. The 2N3055 transistor is mainly used for amplification and switching purposes and its configuration can be done in three different configurations:
CE:Mainly used in amplifier circuits such as switches and voltage regulators.
CB:Mainly used in current drive circuits, such as AC power supplies.
CC:Mainly used for input and output control circuits, such as synchronous control and self-oscillation.

In the case of the CE structure, since the 2N3055 transistor contains a switching frequency of about 3 MHz, the 2N3055 transistor is not used for amplification, so it reduces the gain of the forward current to 1. The maximum VCE (collector to emitter voltage) depends primarily on the anode current strength between the two terminals (e.g., base and emitter), which is supplied by an external circuit.

Ⅰ.Specification parameters of 2N3055

•Transistor polarity:NPN
•Collector-Emitter Voltage VCEO Max:60V
•Collector- Base Voltage VCBO:100V
•Emitter- Base Voltage VEBO:7V
•Collector-Emitter Saturation Voltage:3V
•Maximum DC Collector Current:15A
•Pd - Power Dissipation:115W
•Gain Bandwidth Product fT:2.5 MHz
•Minimum Operating Temperature:-65 C
•Maximum Operating Temperature:+200 C
•Frequency: 1 MHz
•DC current gain (hFE): 70
•Package/casing: TO-204, TO-3

Ⅱ.2N3055 basic working principle

1. Working principle: The working principle of 2N3055 is based on the combination of PNP transistor and NPN transistor. When a positive voltage is applied to the base (Base), this causes the PN junction between the base and emitter to become conductive, allowing electrons to enter the collector from the emitter, forming a collector-to-emitter current (IC). This process is called amplification.
2. Three-layer structure: In 2N3055, there are three different areas. These areas are N-type (Negative) material, P-type (Positive) material and N-type material. This forms a PN junction, in the middle of the PN junction, and another PN junction on both sides. In 2N3055, the usual N-type material is silicon, and the P-type is also silicon. However, due to the doping of some impurity elements (such as copper, cobalt), its electrical properties are changed.
3. Pins: 2N3055 has three pins, namely Base, Emitter and Collector.
Base: By controlling the base current (IB), the current from the collector to the emitter (IC) can be controlled. This control is achieved by changing the electric field of the PN junction.
Emitter: The emitter is where electrons are injected into the transistor and from here they flow towards the collector.
Collector: The collector is where the electrons ultimately flow, and it is responsible for collecting the flow of electrons in the transistor.

4. Amplification: By appropriately adjusting the base current (IB), the collector-to-emitter current (IC) can be adjusted. 2N3055 is a commonly used power amplifier. In this circuit, a smaller input signal IB controls a larger output current. Due to this amplification effect, 2N3055 is used in electronic circuits, especially when amplification of large currents is required.

Ⅲ.Use 2N3055

•Before you start using the 2N3055, it is important to understand its maximum current, maximum power, maximum voltage, pin configuration, and temperature range.
•Design a circuit containing 2N3055. Determine the current and voltage ranges to be amplified or controlled, and the required amplification factor.
•2N3055 usually has three pins, namely Base, Emitter and Collector. According to the circuit design, connect the pins of 2N3055 to other components, ensuring correct connections.
•For NPN type 2N3055, provide appropriate IB through Base to control the conduction of the transistor. This usually involves using a suitable resistor to limit the base current.
•In high power applications, the 2N3055 may generate heat. Therefore, proper heat dissipation is required. The 2N3055 is usually mounted on a heat sink, making sure the heat sink has enough area to dissipate the heat generated.
•Provide appropriate power supply voltage to 2N3055 to ensure that it does not exceed the maximum voltage specified in the manual.
•Before connecting the power supply, carefully check the circuit connections to ensure there are no short circuits or incorrect connections. Apply voltage step by step and carefully observe and record the 2N3055's performance, including output current, voltage, and power.

IV.2N3055 main features

Polarity: 2N3055 is an NPN bipolar transistor, N represents negative polarity (N-type). It has a middle area of N-type material sandwiched between two P-type materials. Current flows at its base end toward the emitter. This is because when current flows from the collector to the emitter, the current passes through the collector and flows from it through the emitter, thereby controlling the current flow from the collector to the emitter.
Pd Max: Pd Max is the maximum power that the 2N3055 can handle, usually expressed in Watts. This characteristic takes into account the heat generated by the 2N3055 when operating and is therefore also related to heat dissipation.
IC Max: The IC Max of the 2N3055 is the maximum current it can sustain continuously. This characteristic is very important because it determines the maximum current value that can pass through the 2N3055 in the circuit.
VCE Max: VCE Max is the maximum collector-emitter voltage that the 2N3055 can withstand. If this voltage is exceeded, the 2N3055 may be damaged.
HFE (or β): This is the current gain or amplification factor between IB and IC. The HFE value is used to describe the amplification capability of 2N3055.
VCESat: When the 2N3055 works in the saturation region, its emitter-to-emitter voltage. In the saturation region, the conductivity of the triode reaches its highest value.

Ⅴ.MARKING DIAGRAM of 2N3055

xxxx55=Device Code
xxxx=2N30 or MJ20
G=Pb−Free Package
A=Location Code
YY=Year
WW=Work Week
MEX=Country of Orgin

Ⅵ.2N3055 package type

1.TO-220 package: TO-220 package is another common 2N3055 package type. Typically used in medium power applications, it is more compact than the TO-3 and suitable for designs requiring less space. TO-220 packages usually have three pins and are easier to mount on a printed circuit board.
2.TO-3 package: This is one of the most common package types of 2N3055. The TO-3 package is a metal package that is typically used in high power applications because it has better heat dissipation properties. The TO-3 packaged 2N3055 usually has threaded metal mounting holes for easy fixing to the heat sink.

Ⅶ.Application fields of 2N3055

•Power amplifier: 2N3055 is mainly used in audio and radio frequency power amplifiers to amplify current signals. It can be used to enhance signal strength and volume in applications such as loudspeakers, sound systems, radio transmitters and more.
•Voltage stabilizer: It can be used to construct a linear voltage stabilizing circuit that can stabilize the output voltage. It is suitable for use in electronic circuits that require voltage stability.
•Switching power supply: 2N3055 can be used in switching power supply circuits to convert DC power into DC power at another voltage level. It is usually used in electronic equipment and power adapters.
•Power level switching: 2N3055 can be used in switching circuits for controlling high current loads such as motor control and relay driving.
•Inverter: 2N3055 can be used in inverter circuits to convert DC power into AC power, suitable for renewable energy systems such as solar panels and wind power.
•Battery charging and discharging: 2N3055 can be used in battery charging and discharging circuits to manage and control the battery charging and discharging process.
•High-temperature applications: Since 2N3055 can operate normally at higher temperatures, it is suitable for some high-temperature environment applications, such as automotive electronics, industrial automation, and military equipment.

Frequently Asked Questions

1.2What are the alternative models of N3055?
Alternative models of 2N3055 are: MJ2955, TIP3055, MJ15003/MJ15004, 2N3773/2N6609, MJE3055/MJE2955, 2SC5200/2SA1943.

2.2What are the thermal characteristics of N3055?
The maximum operating temperature is the highest temperature at which the 2N3055 can operate normally. Exceeding this temperature may cause transistor performance degradation or damage. Usually expressed in degrees Celsius (°C). Thermal resistance represents the thermal conductivity of a transistor, that is, the thermal resistance from the transistor's junction to the external environment. θjc represents the thermal resistance from the chip to the package case, while θja represents the thermal resistance from the chip to the environment.

3. How to test whether 2N3055 is working normally?
Connect the 2N3055 correctly into the circuit. Make sure the pin connections are correct and the supply voltage and load match the requirements in the data sheet. The base connection should be controlled with appropriate resistors to ensure that the maximum base current is not exceeded. Apply the supply voltage stepwise between the collector and emitter of the 2N3055 to activate the transistor. Please ensure that the power supply voltage does not exceed the maximum voltage value in the specification sheet.