The S8050 is an NPN transistor with low voltage and high current that can be used to create Class B push-pull amplifiers. In the bipolar junction transistor S8050, holes are the minor carriers while electrons are the major ones. S8050 is primarily used as an amplifier for boosting low signals, such as audio amplifiers, and has a high DC gain of 300. Before we examine the S8050 datasheet, let's talk about some fundamental usage tenets.

Making a Class B push-pull amplifier out of an NPN transistor

The low-power signal is powered up to a high-power signal using amplifiers. Applications for audio amplifiers include loudspeakers and headphones, among others. The following are the four different types of amplifiers:

 

1. Class A amplifier

2. Class B amplifier

3. Class AB amplifier

4. Class D amplifier

 

 

Amplifiers can be designed in several ways. The one that uses transistors, such as the S8050, is the most common. S8050 amplifiers are typically utilized as Class B Push-Pull devices.

 

Two complementary transistors (one NPN and one PNP) are connected in series with the voltage source and load in a class B push-pull amplifier, as illustrated below.

 

The identical power signal is received by both, but at different phases from one another. During the positive half cycle of the signal, the NPN transistor is forward biased, and the PNP transistor is in operation. A push-pull amplifier is one in which one pushes current through the load while the other pulls current through the load.

 

Here, we can use an S8050 NPN transistor along with a complementary PNP transistor of the same operational characteristics to design a Class B push-pull amplifier.

While selecting a transistor for amplification, some of the key points to consider are:

§ The maximum continuous output power: defines how loud the amplifier can be, often specified for different load impedances, distortion levels, and supply voltage configurations.

§ Gain/Efficiency: ratio of the power turned into sound to the total power consumed by the amplifier. Low efficiency indicates loss of power in terms of heat. This may require a large heat sink which is often out of the question for audio boosting devices. The maximum efficiency of a Class B amplifier is 78.5%.

§ Total Harmonic Distortion + Noise (THD+N): ratio of signal to noise and distortion in the amplifier output

 

 

Here are some notable pieces of information from the S8050 datasheet. For more details, please check the S8050 datasheet.

§ Maximum DC current gain: 300

§ Power dissipation: 1 watt

§ Base-emitter saturation voltage VBE(sat): 1.2 v

§ Collector current: 1.5A

§ Maximum Power: 2 Watt

§ Base- Emitter Voltage ( VBE):  6V

§ Collector-Emitter Voltage (VCE): 25V

§ Collector-Base Voltage (VCB): 40

 

 

This NPN transistor cannot drive loads requiring more than 1.5 volts because its continuous electric collector current (IC) is limited to 1.5 volts. By applying current to the base, the transistor can be biased, but only up to its maximum value. The transistor runs in the forward biased zone when the voltage across the base-emitter junction exceeds VBE(min), which is 0.7V. (transistor gets switched ON). We can use the transistor for amplification because it is in an active region. By altering the input supply voltage, we can bias the output current. The transistor's gain determines the degree of amplification.

The highest DC gain is 300. Until the transistor is in the forward biased condition, the output current can be amplified up to 300 times more than the input current.

The transistor enters the saturation area once it has reached its maximum bias. There, it has a maximum 1.5 amp load capacity at a maximum collector emitter voltage of 25 volts and a maximum collector base voltage of 40 volts. The transistor enters the cut-off zone when there is no base current and remains off.

 

 

S8050 in Push-Pull Configuration

In the above section, we’ve mentioned that the transistor is common in push-pull configurations. 

Ideally, you’ll require to assemble two complementary transistors. Thus, while one is an NPN, the other is a PNP.  The two should also be identical. 

In this case, your NPN is the s8050. Hence, you can pair it with a PNP transistor such as S8550. 

 

S8050 transistor Advantage

The overarching advantage of the transistor primarily relies on its high gain capacity. Normally, its gain can rise to 400. In terms of amplification capacity, such a gain value is valuable. 

Also, its gain can be low, especially when under normal operating current. Therefore, it offers a range that engineers can exploit in the creation of electronics. Thus, the high and low gains allow for various levels of amplification. 

Where Can We Use S8050 transistor & How to Use it？

You can regard the S8050 as a general-purpose transistor. Thus, it finds use in various types of circuits for small and general uses. For example, in electronic circuits that require a switch, the transistor is useful. 

Also, it will perfectly control loads that are below the 700mA threshold. Note that this current is sufficient in running most of the small power household appliances. For instance, it is suitable for running LEDs, relays, and bulbs. 

The other typical application is in the amplification processes. Alternatively, you can apply it in the separate amplification of small signals.

 

How to Safely Long Run S8050 in Circuit？

If you are looking to use this transistor for your project, there are several vital precautions. First, make sure you use it with a voltage below 20V. 

Also, make sure that you don’t connect a load that exceeds 0.7 A. 

Additionally, make sure to operate it under the right temperature range. Ideally, it should be between 150 degrees celsius and -60 degrees celsius.