Last Updated on October 22, 2023 by Kevin Chen
Image source Freepik
Whenever there is a talk about transistors, two things that must be mentioned are the switch and amplifier. These are the two major functions of transistors in electronic applications. These three-terminal semiconductor devices have two major properties that enable them to perform various functions. These properties are the n-type and p-type materials.
When the p-type and n-type materials are combined, they end up forming a depletion layer which will work as a switch and amplifier when you connect the transistor to an electric circuit.
Ever since the first transistor was invented in 1947, a lot has improved in this field of electronics. Transistors have undergone a gradual evolution. They have become smaller and more effective. They have also become cheaper and are used for running modern electronic devices. In this article, we are going to discuss in detail the common applications of transistors in electronics.
How do transistors work?
Before we look at the application areas, it will be prudent to have an overview at the working mechanism of transistors.
As we have already mentioned, transistors can work as switches. This happens when they control the flow of electric current. They can turn it ON and OFF just like ordinary switches. The second function is to amplify the current. They receive a low current and ensure that it gives a higher output current.
The working principle of transistors involves all three terminals, collector, base, and emitter. The configuration of the transistor can either be NPN or PNP. This is all about the arrangement of the transistor layers.
When there is no current flowing through the base, the transistor directly implies that there will be no flow of current through the collector and emitter terminals. The transistor will remain at the ‘off’ state and the same applies to the circuit.
When there is a flow of current through the base terminal, it will flow through the collector all the way to the emitter. The transistor will get into an ‘On’ state and so will the circuit.
Application areas of transistors
Image source Freepik
Let’s look at some of the most common applications of transistors in electronics.
This is a direct application of transistors in modern electronics. They are used as signal amplifiers whereby the ensure that the output electronic signal is higher than the input signal. This is necessary when you want to get the best output from an electronic device. The transistors are capable of amplifying the signals without affecting the quality of the signal being transmitted.
A transistor will function as an amplifier when the DC voltage is applied across the emitter-base junction. This connection will ensure that the transistor remains in a forward bias condition regardless of the state of the input signal. The low output resistance in the transistor will result in a high voltage drop across the load resistor. This will end up amplifying the output signal.
Amplifier circuits are quite common in many electronic devices and applications. Audio and visual electronic devices are the most common applications that must have amplifier circuits.
The operation of microphones fully depends on the transistors. Although there are different types of microphones, all of them tend to utilize one or two features of transistors to ensure that they perform intended tasks effectively.
Condenser microphones, for instance, are designed to convert mechanical waves into electrical signals in order to modify impedance. This task is done by field effect transistors (FET) which in this case act as a transducer. It accepts the audio waves as input signals and produces it in the form of amplified electronic signals.
Transistors are positioned right between the input and output sections of the microphones to facilitate a smooth flow of electrical signals. The output signals from the transistor are connected to the output section of the microphone where they will be directed to an output audio device.
Used in electronic switches
Switching is another major function and application of transistors in electronics. On their own, they can implement the switching functionality. They still execute the same function when embedded in other electronic devices and appliances.
The ability of transistors to work as switches is mainly because they have three major operation regions. These are the active region, saturation region, and cutoff region. In the saturated state, there is a maximum flow of current in the transistor while in the cut-off region, there is minimum flow of current as the voltage will be at the peak. A transistor will work as a typical switch when it operates in these two regions. It will turn the circuit on and off.
The lightweight construction of transistors makes them better switches. They are able to change the states of the circuit rapidly. The fact that they are small also makes sit easy to integrate them into different electronic circuits. There is also minimum noise from the transistors when performing the switching operations. This is due to the minimalistic design whereby there are few mechanical components.
This is another old-age application of transistors in electronics. They were used for making audio aid devices. The se device is embedded with microphones that accept audio signals as input and converts them into electronic signals. After the conversion, these signals are amplified and this is where transistors come in.
Other than signal amplification, transistors filter the signals to improve the audio characteristics of the output signals. Some hearing aids have the capacity to translate audio signals from one language to another. This can only happen after transistors amplify, filter, and smoothen the signals.
Additionally, think about the compact size of the hearing devices. It is possible to achieve such designs thanks to the small size of transistors. This implies that other than functionalities, transistors have a direct impact on the design of hearing aid devices.
Use of transistors in lasers
Transistor lasers are also known as light-emitting transistors. They are designed to emit focused light that is channeled to a single direction. This device is mainly used in the communication industry where they facilitate fast data transfer.
Laser transmitters work in a similar manner to laser diodes though they are faster and offer more data integrity.
The working mechanism of smoke detectors is due to the presence of transistors, and other electronic components. These electronic parts include a potentiometer and light-emitting diode smoke sensors among others. Each component on the smoke detector has a special role that it plays in the overall working of this device.
Transistors in the smoke detectors control the signals that are associated with smoke detection. The transistors are connected to the circuits that are responsible for manipulating the signals for smoke detectors. In such a case, the transistor will serve as a switch. The high speed of transistors will turn the detector on in case the signals sent a message about the presence of smoke in the room.
Transistors are the building blocks of microprocessors, which are responsible for controlling and determining the operations of computers and other electronic devices. A single microprocessor comprises thousands of interconnected transistors.
Switching is a major function of transistors that is used by microprocessors. It is applicable in the data processing and storage capabilities of the microprocessors. The logical operation of the microprocessor depends on the arrangement of the transistors.
This is another common application of transistors in electronics. Air conditioning units are designed to improve the room temperature to the desired levels. How do air conditioners that inside temperature is low or high? It is all about the signals and the sensors. Transistors tend to feature heavily in matters relating to signal sensing and transfer.
Circuits in the sensors are embedded with transistors that control and determine the temperature ranges at which the HVAC should operate.
Integrated circuits are almost in every electronic device. Each IC is packed with thousands of transistors that implement different functionalities. Power transistors are used for power management in the integrated circuits. Others are used ion the data processing and security functionalities of the integrated circuits. The number of transistors in integrated circuits will vary from one IC to another.
From the above list of transistor application areas, it is clear that transistors are integral in the world of electronics. They are literally run all the modern electronic devices and appliances. Whether small or large appliance, it will feature transistors.
The type of transistors used and the functionality will depend on the specifications of the device and its application areas. For example, transistors for audio systems are mainly used for signal amplification while in power devices they are used as switches.
Are you working on an electronics project? There is a high chance that it will entail the use of transistors. Start by knowing the type of transistor that will be used for your electronic application. From there, you can proceed to buy from reputable and reliable transistor suppliers in China. Inquire about all the necessary details, including the specification and price of the transistors for sale.
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