MOSFET BJT or IGBT - Brief comparison Basic components #004

Electronoobs

16 Jun 201908:38

Summary

TLDRThis video explores the key differences between three types of transistors: MOSFETs, BJTs, and IGBTs. It explains how each type works, their advantages, and when to use one over the other, depending on factors like current, voltage, and application. The video covers aspects such as power control, switching speed, circuit complexity, and cost, helping viewers choose the right transistor for their projects. Additionally, the creator provides helpful diagrams and parameters to consider when selecting components. The video also includes a sponsorship from JL CPCB, discussing PCB production services.

Takeaways

📢 The video discusses the differences between MOSFETs, BJTs, and IGBTs, and their suitability for various electronic projects.
🔍 The choice between these transistors depends on the application area, load power modulation technique, and frequency requirements.
📡 BJTs are represented with a collector, emitter, and base, and their output current is controlled by the base current.
💧 MOSFETs have a drain, source, and gate, with current flow controlled by the voltage applied to the gate.
🔌 IGBTs combine features of both BJTs and MOSFETs, with an emitter, collector, and gate control like a MOSFET.
🔋 BJTs are high voltage, low current devices with complex base drive requirements.
💪 MOSFETs are high current, low voltage devices with simpler gate control circuits.
🏭 IGBTs are high voltage and high current devices with lower conduction losses but slower switching speeds.
📊 A three-dimensional graph is used to illustrate the maximum current, frequency, and voltage capabilities of each transistor type.
📄 When selecting a transistor, consider parameters like continuous current rating (IC), current gain (hFE), on voltage, turn-off time, and breakdown voltage.
💰 Cost is an important factor, with BJTs being the cheapest, MOSFETs medium-priced, and IGBTs generally more expensive.

Q & A

What are the three types of transistors discussed in the video?
-The video discusses MOSFETs, BJTs (Bipolar Junction Transistors), and IGBTs (Insulated Gate Bipolar Transistors).
What is the primary function of these power semiconductor components?
-The primary function is to control the current through a load in a controlled manner, which could be fully on, fully off, or something in-between.
How does the current flow in a BJT?
-In a BJT, current flows between the collector and the emitter, and this flow is controlled by the signal applied to the base.
What is the control type for a MOSFET?
-The current flow between the drain and the source in a MOSFET is controlled by the voltage applied to the gate.
How does an IGBT differ from a MOSFET and a BJT in terms of control?
-An IGBT is a mix between a MOSFET and a BJT. It has the emitter and collector like a BJT, but it is controlled by a signal applied to the gate, similar to a MOSFET.
What are the typical applications of BJTs, MOSFETs, and IGBTs?
-BJTs are typically used for high voltage and low current applications, MOSFETs for high current and low voltage applications, and IGBTs for high voltage and high current applications.
What are the key parameters to consider when selecting a BJT?
-Key parameters for a BJT include the continuous current rating (IC), current gain (hFE), on voltage, turn off time, and breakdown voltage.
What parameters are important to check for a MOSFET?
-For a MOSFET, it's important to check the threshold voltage, current rating, and on resistance.
How does the cost generally compare between BJTs, MOSFETs, and IGBTs?
-BJTs are usually the cheapest, followed by MOSFETs at a medium price, and IGBTs are generally more expensive.
What is the significance of the three-dimensional graph for applications mentioned in the video?
-The three-dimensional graph helps to visualize the maximum current, maximum frequency, and maximum voltage capabilities for each type of transistor, aiding in the selection process based on specific circuit requirements.
Why might one choose an IGBT over a BJT or a MOSFET?
-One might choose an IGBT over a BJT or a MOSFET because IGBTs combine the high voltage and current handling capabilities of BJTs with the simple gate control of MOSFETs, making them suitable for applications requiring high power management with lower switching losses.

Outlines

00:00

🔬 Introduction to Transistors: MOSFETs, BJTs, and IGBTs

This paragraph introduces the topic of the video, which is a comparison and explanation of three types of transistors: MOSFETs, BJTs, and IGBTs. The video aims to address common questions about when to use each type, their differences, and which might be best suited for various projects. The narrator encourages viewers to subscribe and activate notifications to stay updated with future videos. The video is sponsored by JL CPCB, which is highlighted for its new PCB batch production capabilities and competitive pricing. The paragraph sets the stage for an in-depth look at the characteristics and applications of each transistor type, emphasizing the importance of understanding their roles in circuit design, such as motor control, power supply, and audio amplification.

05:01

📊 Transistor Comparison: Characteristics and Applications

This paragraph delves into the specifics of how each transistor type functions and their key characteristics. It explains the fundamental purpose of power semiconductor components, which is to control the current through a load in a controlled manner. The BJT is described as a high-voltage, low-current device with complex base drive requirements, suitable for applications up to thousands of volts but limited to a few amps. The MOSFET is characterized as a high-current, low-voltage device with simpler gate control, capable of handling high currents but limited to around 100 volts. The IGBT is highlighted as a high-voltage, high-current device with lower on-state losses and simpler gate control, although it has slower switching speeds. The paragraph also introduces a three-dimensional graph to visualize the maximum current, frequency, and voltage for each component, helping to clarify their application areas. Additionally, it outlines important parameters to consider when selecting transistors, such as continuous current rating (IC), current gain (hFE), on-voltage, turn-off time, and breakdown voltage for BJTs; threshold voltage, current rating, and on resistance for MOSFETs; and similar parameters for IGBTs, with the added note that IGBTs do not have a current gain. The paragraph concludes with a reminder of the importance of cost considerations when selecting components, with a general price trend from low for BJTs to medium for MOSFETs and higher for IGBTs.

Mindmap

Keywords

💡MOSFET

MOSFET stands for Metal-Oxide-Semiconductor Field-Effect Transistor. It is a type of transistor used for amplifying or switching electronic signals and electrical power. In the video, MOSFETs are described as high current but low voltage devices with a simple gate control circuit. They are suitable for applications requiring high current loads but only up to around 100 volts. The script explains that the current flow between the drain and the source of a MOSFET is controlled by the voltage applied to the gate, modulating the channel resistance.

💡BJT

BJT stands for Bipolar Junction Transistor. It is a type of transistor that allows current flow between two layers of semiconductor material. The video script highlights BJTs as high voltage and low current devices, suitable for applications with low current but high voltage requirements. The control of current in BJTs is dependent on the current applied to the base, as mentioned in the script, where a small current at the base results in a larger current flow between the collector and the emitter.

💡IGBT

IGBT stands for Insulated Gate Bipolar Transistor. It is a three-terminal power semiconductor device primarily used in high-power applications. The video describes IGBTs as high voltage and high current devices, combining the characteristics of both MOSFETs and BJTs. They have lower losses when turned on and a simpler gate control circuit, but their switching speeds are relatively low. The script uses IGBTs as an example of a component that can withstand good voltage and current values, making them very interesting for certain applications.

💡Transistor

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is a key component in modern electronic devices. The video script discusses the use of different types of transistors for various applications, emphasizing their role in controlling current flow through a load in a controlled manner. The script explains the differences between MOSFETs, BJTs, and IGBTs in terms of their control mechanisms, current and voltage capabilities, and applications.

💡Gate

In the context of transistors, the gate is a terminal that controls the flow of current between other terminals. The video script explains how the gate in MOSFETs and IGBTs controls the current flow by applying a voltage, which modulates the channel resistance. For BJTs, the base is the equivalent of the gate in controlling the current flow, but it does so by current rather than voltage.

💡Control Type

Control type refers to the mechanism by which the current flow in a transistor is regulated. The video script distinguishes between the current-controlled nature of BJTs, where the base current controls the collector-emitter current, and the voltage-controlled nature of MOSFETs and IGBTs, where the gate voltage controls the current flow. This distinction is crucial for understanding how each type of transistor can be used in different circuit designs.

💡Current Rating

Current rating is the maximum amount of current that a component can safely carry. The video script mentions that for BJTs, the continuous current rating (IC) is an important parameter, while for MOSFETs, the current rating is considered along with the on resistance. Understanding the current rating is essential for selecting the appropriate transistor for a circuit that can handle the required load current without overheating or damaging the component.

💡Voltage Rating

Voltage rating is the maximum voltage that a component can withstand before breaking down or becoming damaged. The video script discusses how BJTs can operate at high voltages, while MOSFETs are limited to lower voltages but can handle higher currents. For IGBTs, both high voltage and high current capabilities are highlighted, making them suitable for high-power applications.

💡Switching Speed

Switching speed refers to how quickly a transistor can transition from an 'on' state to an 'off' state and vice versa. The video script notes that BJTs can be switched up to speeds of around 100 kHz, MOSFETs up to 500 kHz, and IGBTs around 50 kHz. This parameter is critical for applications requiring fast response times, such as in power electronics and motor control.

💡On Resistance

On resistance is the resistance of a transistor when it is in the 'on' state, allowing current to flow. The video script mentions that for MOSFETs, the on resistance is an important parameter to consider, as it affects the efficiency of current flow and the power dissipation in the transistor. Lower on resistance is generally desirable for high-power applications to minimize energy loss.

💡Cost

Cost is a consideration in the selection of electronic components, including transistors. The video script discusses the relative costs of BJTs, MOSFETs, and IGBTs, noting that BJTs are generally the cheapest, followed by MOSFETs, with IGBTs being more expensive. The cost can influence the choice of transistor for a project, especially when considering budget constraints or the need for a large quantity of components.

Highlights

Introduction to the topic of transistors: MOSFETs, BJTs, and IGBTs, and their applications.

Explanation of the basic function of power semiconductor components to control current through a load.

Icon representation and structure of Bipolar Junction Transistors (BJTs).

Icon representation and structure of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs).

Icon representation and structure of Insulated Gate Bipolar Transistors (IGBTs), highlighting their hybrid nature.

Control type differences between BJTs, MOSFETs, and IGBTs.

BJTs described as high voltage and low current devices with complex base drive requirements.

MOSFETs characterized as high current and low voltage devices with simpler gate control.

IGBTs as high voltage and high current devices with lower losses and simple gate control.

Three-dimensional graph for applications showcasing max current, frequency, and voltage for each transistor type.

Practical applications of each component as a power control device.

Parameters to consider when selecting BJTs, including continuous current rating and current gain.

Parameters for MOSFETs, such as threshold voltage, current rating, and on resistance.

Parameters for IGBTs, which are similar to BJTs but without current gain.

Cost considerations for different transistors, with BJTs being the cheapest, followed by MOSFETs and IGBTs.

Encouragement for viewers to subscribe and activate notifications for future videos.

Call to action for supporting the creator's work on Patreon.