This section provides an overview for power transistors as well as their applications and principles. Also, please take a look at the list of 10 power transistor manufacturers and their company rankings.
A Power Transistor is a transistor with an allowable power of 1W or more in operation. They are used in electrical devices that are driven by large currents.
The main roles of power transistors are current amplification, switching, and rectification of alternating current.
Because of the large currents they handle, they generate a lot of heat during operation, and so products have heat-resistant metal cases or fins for heat dissipation.
There are several types of power transistor, with bipolar power transistors, MOSFETs, and IGBTs being the most common.
Power transistors are used for applications such as switching and current amplification in electrical equipment that requires a large current to operate. Typical applications include home appliances such as air conditioners, refrigerators, and washing machines, solar power generation, and electric vehicles.
Depending on the application, the allowable current, voltage, heat generated during operation, size, and other factors must be considered. If the destination is a product that needs to operate with high precision, the switching speed and other factors should also be taken into consideration to switch the current flowing through the circuit and amplify the current.
The principle for the operation of power transistors varies depending on the type.
A bipolar transistor is a transistor with a structure consisting of three layers of N-type and P-type semiconductors joined together.
The semiconductors that make up the bipolar transistor have terminals coming out of each semiconductor, which are called the base, emitter, and collector. With voltage applied to the emitter and collector, a large current flows between the emitter and collector when current flows in the base.
A MOSFET is a transistor with a structure similar to a bipolar transistor. The terminals are named source, drain, and gate. When voltage is applied to the gate, current flows between the source and drain.
Because of its high-speed switching capability, this transistor is used in products that require quick control.
An IGBT is a transistor with the same structure as the above two transistors. The terminals are called gate, emitter, and collector. The structure is a combination of the emitter and collector from a bipolar transistor and the gate adopted from a MOSFET.
This type of transistor has the good points of the above two transistors and has a wide range of applications.
There are two main types of power transistor: bipolar transistors and field-effect transistors.
A bipolar transistor is a current control device. There are NPN and PNP types depending on how the semiconductors are stacked. They generally have three terminals, two paths for the output current and one input that controls the output current.
An emitter-grounded circuit is typically used, with the input signal at the base (B), the + supply at the collector (C), and the emitter (E) grounded. The DC current amplification factor of a bipolar transistor is expressed as β or hFE and ranges from tens to 200.
Power transistors with Darlington configuration are also available to earn β (β is in the hundreds to thousands).
Field-effect transistors, on the other hand, are voltage-controlled devices and come in N- or P-channel structures.
They typically have three terminals, two paths for the output voltage and one input that controls the output voltage. A source-ground circuit is typically used, with the input signal on the gate (G), the + supply on the drain (D), and the source (S) grounded.
The DC voltage amplification factor of an electrolytic effect transistor is expressed in terms of mutual conductance (gm). They have better switching characteristics than power transistors and are often used in switching power supplies.
If a transistor, which is often used in output and power supply sections, fails, the output of the circuit may be lost or become unstable. Therefore, it is important to check for transistor failure.
1. NPN transistor
For NPN transistors (2SC or 2SD), check the following:
If all three of these are true, the transistor is okay.
2. PNP Transistor
In the case of a PNP transistor (2SA or 2SB), the reverse direction is true.
If all three of these conditions are satisfied, the transistor is okay.
Note: this test cannot be used for Darlington transistors.
When the tester is used in the continuity range, the red side is negative and the black side is positive. Pay attention to the polarity of the test voltage on the tester leads. Also, be sure to disconnect the power supply, input wires, output wires, etc. of the non-test object before testing.
*Including some distributors, etc.
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Broadcom Inc., established in 1961, and headquartered in San Jose, California, is a manufacturer and supplier of semiconductor and connectivity solutions. The company specializes in producing products, such as semiconductors, infrastructure software, networking products, storage products, wireless products in which their products cater to industries such as telecommunications, data centers, and consumer electronics. Their products are used for various applications, including wireless communication, networking equipment, data storage, and multimedia devices, providing components for advanced technologies in numerous industrial and commercial sectors.
Integra Technologies, founded in 1997, is a manufacturer and supplier of RF power devices located in El Segundo, California. The company specializes in providing radar signal amplification solutions, encompassing RF power transistors, RF power amplifier modules, and RF power pellets. These products are designed to handle high-power RF signals efficiently and are used in various applications, such as avionics, defense, instrumentation, and weather radar. Integra Technologies ensures continued support for legacy programs and offers customization options to meet specific design requirements.
Solitron Devices, Inc., based in West Palm Beach, Florida, is a manufacturer of solid-state semiconductor components and related devices, primarily serving the military and aerospace markets, founded in 1959. The company offers a wide range of products, including bipolar and metal oxide semiconductor power transistors, power and control hybrids, thin film resistors, and other related products. They have been manufacturing power semiconductors and integrated power solutions for systems that demand the ultimate in performance. Customers in aerospace, defense, industrial and space rely on their products to develop smaller, lighter weight, higher efficiency systems level solutions.
Applied Power Systems, Inc. (APS) was founded in 196 and headquartered in Hicksville, New York. Applied Power Systems is a power electronics company specializing in power conversion systems and thermal management of high power semiconductors. APS offers a large selection of high power thermal management products. These products include standard and custom aluminum extrusion heat sinks for natural convection and forced air-cooling. Cast and machined copper chill plates for liquid cooling. State of the art clamps for flat pack or hockey puck semiconductors. APS also offers driver circuit boards to drive SCR, IGBT and MOSFET devices.
RFMW has been a supplier and distributor of specialized radio frequency (RF) and microwave components since it was founded in 2003 and is based in California. They provide RF & Microwave and Power Component distribution that focuses on Technical and Supply Chain Solutions and these include Active Devices like Diodes, Transistors, Amplifiers, Control Components, and more along with Passive devices such as Filters, Inductors, Antennas and alike. They also have Power Management and Interconnect/T&M components which help them serve military, aerospace, test, measurement, medical, and commercial markets.
Toshiba Electronic Devices & Storage Corporation is a division of Toshiba focusing on providing designs for end-product developers as well as semiconductor and drive equipment for automotive, industrial equipment, green energy, and consumer and personal electronic devices. Toshiba’s storage products include cloud-scale and enterprise-level products, and PC hard drives. Semiconductor products include Si Cower devices, MOSFETs, IGBTs, IEGTs, isolators, solid state relays, power management and intelligent power ICs, diodes, bipolar transistors, microcontrollers, automotive devices, ICs for wireless communication equipment, general purpose logic ICs, radio-frequency devices, sensors, and linear image sensors.
Renesas Electronics Corporation was established in 2002 and is headquartered in Tokyo, Japan. Renesas is a global research, design, and manufacturer of semiconductors used in industries spanning automotive, consumer electronics, the internet of things, power & energy, and industrial sectors. Renesas manufactures both analog and digital products. Analog products include amplifiers, audio & video devices, data converters, PLC, and switches & multiplexers. Digital products include microcontrollers, memory components, sensors, wireless connectivity products, and others. Renesas also offers design resources such as kits, development tools, partner programs, and design tools.
NXP was established in 2006 as a spinoff from Phillips and is headquartered in Eindhoven, Netherlands. The company is a co-founder of NFC communication and designs and manufactures semiconductors that serve the automotive, industrial, mobile, and smart home industries. The company’s automotive products include driver assistance transceivers, sensors, and security systems. For industrial markets, the company produces RFID readers, processors, and microcontrollers. For communication infrastructure, the company produces RF mixers, diodes, and low-noise amplifiers for wireless LAN networks. The company also produces peripherals, power management chips, communications chips, and interface devices.
ST Micro Electronics is a global semiconductor company serving customers with innovations to have a positive impact on people's lives. Their product line is micro electronic systems, such as switches, controllers, sensors and drivers. The main selling point of ST Micro Electronics is its provision of sustainable products, and introducing their electronics to create a more sustainable world. The company, as well as providing the electronic devices, also provides software and support, ensuring that all fields are covered to provide a fully provide a supported and strong relationship with their customer base. ST Micro Electronics believe that technology plays a key role in helping to solve environmental and social challenges, which is why their semiconductor technologies start with their employees, their customers and partners.
ROHM Semiconductor was incorporated in 1940 and is headquartered in Kyoto, Japan. ROHM manufactures and sells electronic components worldwide. ROHM operates through the segments ICs, discrete semiconductor devices, and modules. ROHM provides ICs comprising memory, amplifiers and linear, power management, clocks and timers, switches and multiplexers, logic, data converters, sensors and MEMS, display drivers, motor/actuator drivers, interfaces, communication and speech synthesis LSI, audio and video, and microcontrollers. ROHM also offers discrete semiconductor products include MOSFETs, bipolar transistors, and diodes; power devices, including power transistors and diodes, SiC power devices, IGBT, and IPM; passive devices, such as resistors, and conductive polymer and tantalum capacitors; and various modules among others.