Hi, friends welcome to the new post. In this post, we will have a detailed look at Transistor Symbols. Transistors are crucial, as everyone who is interested in electronics is aware. They are the main component of electronic projects and industry and are used in different devices such as computer circuits, radio, amplifiers and switches. Understanding transistor symbols is essential for beginners since they make it easier to read and comprehend circuit schematics. The definition, terminals, and working parameters of the transistor diagram symbol will be covered in this post with detailed. So let’s get started with Transistor Symbols.
What is a transistor?
- A semiconductor device called a transistor has the ability to switch or amplify electronic signals. The transistor emitter, base, and collector are three layers of semiconductor material that make up the device. The voltage given to the transistor’s base determines how much current flows through it.
- Bipolar junction transistors (BJTs) and field-effect transistors (FETs) are two basic transistor types. Different symbols used for the explanation of the features and structure of these transistors
Transistor Symbols
- Each type of transistor has a distinctive symbol that symbolizes its characteristics, and BJTs and FETs have symbols that are distinct from one another.
Bipolar junction transistor (BJT) symbol
- The emitter, base, and collector are the three sections that make up a BJT’s symbol. A line pointing in the direction of the emitter is used to depict the collector, while an arrow is in an outer direction that is used for the transistor emitter.. A line joining the emitter and the collector serves as the representation of the base.
- NPN and PNP are the two different subtypes of BJTs. The transistor’s polarity influences the voltage levels needed for biassing as well as the direction in which current flows.
Related Topics
A field-effect transistor (FET) symbol
- The gate, source, and drain make up the FET symbol. A line connecting the source and the drain that is parallel to the channel serves as the gate’s representation. The drain is symbolized with an arrow that is outward from the channel while the source is shown through an arrowhead that is the opposite direction.
- FETs come in N-channel and P-channel varieties. The kind of FET influences the voltage levels needed for bias as well as the current flow direction.
Terminals of Transistor Symbols
Each terminal on a BJT and a FET is distinct from the others and is essential to the operation of the transistor.
BJT terminals
- The emitter, base, and collector are the three terminals found on BJTs. The power supply’s emitter and collector are attached to its negative and positive terminals, respectively.
- The control circuit is configured with a base terminal that controls the current flow in the transistor
FET terminals
- Source, Gate, and Drain are the three terminals found on FETs. The drain is connected with the positive terminal and the source is with the negative terminal of the battery The gate regulates the current flowing through the transistor and is coupled to the control circuit.
Tunnel Transistor Symbols
- The emitter and collector are the two sections that make up the tunnel transistor symbol. The transistor’s base is shown the representative for the transistor emitter, and other point work as representatives for the transistor’s collector.
- The base area of a tunnel transistor is not distinct from that of other types of transistors. Instead, a narrow portion of the semiconductor material that enables electron tunneling separates the emitter and collector.
- The symbol for a tunnel transistor can be seen here
Unijunction Transistor Symbol
The emitter, base 1, and base 2 are the three sections that make up the UJT symbol. Base 2 is dented with a straight line that links the opposite point of base 1 and the emitter is through a diagonal line that links with base 1
The UJT symbol is here
It is significant to remember that the UJT symbol might change based on the transistor’s brand and model. To guarantee appropriate identification and operation, it is thus always advised to reference the datasheet of the UJT being used in a circuit.
Phototransistor Symbol
- With the addition of arrows pointing towards the base, the symbol for a photo-transistor is identical to that of a conventional transistor. The light input that causes the transistor to be triggered is shown by these arrows.
The photo-transistor symbol is here
- It’s vital to remember that depending on the manufacturer and the particular transistor type, the direction of the arrows in the photo-transistor sign might change. To guarantee appropriate identification and functioning, it is usually advised to refer to the datasheet of the photo-transistor being used in a circuit.
Avalanche Transistor Symbol
The symbol used to represent an avalanche transistor is similar to that of a regular transistor, with the addition of a small arrow pointing toward the collector. This arrow represents the avalanche breakdown that occurs in the transistor.
Schottky transistor Symbol
- A little arrow pointing towards the collector has been added to the standard transistor’s symbol to depict an avalanche transistor. The avalanche breakdown in the transistor is depicted by this arrow.
The avalanche transistor symbol is here
PUT Symbol
- Two diodes facing each other with a gate terminal in the middle make up the symbol for a PUT. The base of the manufactures, gate terminal is shown through an arrow having directions from left to right
The PUT symbol is drawn here
- It’s vital to remember that the PUT symbol might change based on the transistor’s manufacturer and model. To guarantee appropriate identification and functioning, it is thus always advisable to study the datasheet of the PUT being used in a circuit.
Operating Conditions of Transistor Symbols
- Biasing, amplification, and switching are the three different operating modes for transistors.
Biasing
- Setting the DC voltage and current levels in a transistor circuit is the process of biassing. Biassing is used to keep the circuit stable and to make sure the transistor runs in a particular mode.
Amplification
- Using a transistor, amplification is the process of making an electrical signal stronger. A modest input signal is applied to the transistor in amplification mode, and the result is an output signal that has been amplified. The weak audio signal from a microphone or radio is amplified to a level that can drive a loudspeaker using this mode, which is frequently employed in devices like audio amplifiers.
Switching
- Switching is the process of applying a control signal to switch on and off the flow of current via a transistor. When operating in switching mode, the transistor functions as a switch and is either on or off. Devices like power supply and digital logic circuits frequently employ this mode.
Transistor operating conditions
- Understanding a transistor’s working conditions is crucial for effective utilization. These include the biassing criteria and the maximum ratings.
Maximum ratings
- The absolute maximum voltage, current, and power that a transistor may withstand without experiencing damage are referred to as maximum ratings. The transistor may sustain irreparable damage if these values are exceeded.
- The transistor datasheet contains the manufacturer’s recommended maximum ratings. The following are some of the most significant maximum ratings:
- Maximum collector-emitter voltage (VCEO)
- Maximum collector current (IC)
- Maximum collector-base voltage (VCBO)
- Maximum emitter-base voltage (VEBO)
- Maximum power dissipation (Ptot)
Biasing conditions
- The DC voltages and currents that are provided to the transistor to place it in the correct operating mode are referred to as biassing conditions. To guarantee that the transistor works inside its safe operating area (SOA) and to achieve the intended performance, proper biassing is crucial.
- Fixed bias, self-bias, and emitter bias are a few examples of biassing. Each kind is employed in various kinds of circuits and has different benefits and drawbacks.
Common Mistakes in Interpreting Transistor Symbols
- Transistor symbol interpretation can be challenging, and newcomers frequently make certain errors. Confusion between a BJT’s emitter and collector terminals is one of the most frequent errors. Another error is to believe that the direction of current flow in a FET is indicated by the arrow in the symbol.
- It’s critical to comprehend the transistor’s structure and characteristics as well as the circuit layout in order to avoid committing these errors.
Advantages and Disadvantages of Transistors
- Comparing transistors to other electronic components like vacuum tubes, they provide a number of benefits. It uses less energy and has a compact structure. They may be employed in various applications and work at faster speeds and higher frequencies.
- Transistors do, however, have several drawbacks. Their production cost is high and there are susceptible to getting damaged by static energy
Applications of Transistors
- From straightforward circuits like lamps to sophisticated gadgets like computers and smartphones, transistors are employed in a broad variety of electronic devices. Transistors are often used in TVs, amplifier circuits, radios, digital logic circuits, power supplies, and voltage regulators, among other devices.
Conclusion
comprehension and creating electrical circuits need a thorough comprehension of transistor symbols. The definition, terminals, and working circumstances of transistor symbols were covered in this article. We also covered the benefits and drawbacks of transistors and looked at some typical blunders made when reading transistor signals. Finally, we looked at some typical transistor applications.
To prevent errors that might harm your circuit, always study and comprehend circuit designs carefully. You should also double-check your understanding of transistor symbols.
