High Power Transistor Switch Applications

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A transistor is a semiconductor device that is the basic building block for all digital components. Its primary purpose is to amplify and regulate a specific voltage level, particularly low-level ranges. Various transistor types have emerged over the years, each with its own functions and applications. One of these is the power transistor — a better-suited type for devices operating at high voltage levels.

This article will look at the basics of using a power transistor as a switch and its applications.

Using a Power Transistor as a Switch

A transistor is widely used for switching operations, such as opening or closing a direct current (DC) circuit. In most cases, transistor switches are required to switch low DC ON/OFF when it is cut off or saturated. They are also distinct from Triac switches, which are frequently used for power control in alternating current (AC) systems with higher power switching requirements.

A power transistor is a three-terminal electronic device made of semiconductor materials. It is specifically intended to regulate high current-voltage ratings. Moreover, when voltage or current is applied to one pair of terminals, this device controls the other pairs. This is particularly useful for high-power electronic devices like lamps, solenoids, relays, and motors.

Here are other advantages of a power transistor:

  • High electric current density
  • High voltage gain
  • Large bandwidth gain
  • Low forward voltage

MagneLink integrates power transistors into some of our magnetic switch models.  These types of switches are ideal when switching a heavier duty, inductive-type load in a DC voltage circuit.  In this way, we create a more rugged switch that can endure the current spikes that often occur when switching a relay or a starter coil in a motor.

Common Applications of High-Power Transistor Switches

Power transistor switches are ideal for high-power, current, or voltage applications. Consequently, they are utilized in the following:

Switched-Mode Power Supplies (SMPS)

A switched-mode power supply (SMPS) is an electronic power source that includes a switching regulator for efficient energy conversion. It uses fast-switching components such as power transistors, which internally switch between ON (saturated) and OFF (cut-off) states, resulting in lower energy dissipation.


Relays are electromechanical devices that utilize an electromagnet to move a pair of contacts from open to close. Although numerous designs and types of relay circuits exist, many small electronic installations use power transistors as their primary switching devices. This is because of their ability to quickly control the relay coil from a wide range of input sources.

DC to AC Converters

Power transistors are efficient switching devices for converting power from DC to DC, DC to AC, or AC to DC. They are more dependable than standard electronic vibrators and are not as intricate or bulky as motor generators.

Power Amplifiers

The need for a power transistor switch as an amplifier arises when we want to increase or intensify the input signal. It works by taking in weak signals through the base junction and raising their strength. Then, the amplified signals are released via the collector.


An inverter is a power electronic device or circuitry that transforms DC to AC. It is frequently used to operate appliances, including electric lights, microwaves, power tools, and computers.

Inverter circuits started using power transistor switches that can be turned off via control signals as their preferred switching components. This is due to the availability of these transistors in higher voltage and current ratings.

Power Control Circuits

A transistor acts as a variable resistor in a circuit, regulating its collector-emitter current to keep the output voltage constant. It also controls current flow through one channel by modifying the intensity of a much smaller current that flows through a second channel.

MagneLink for High-Quality Transistor Switches

For more than 25 years, MagneLink has been offering the best and most cost-effective magnetic switches on the market. We also create products for manufacturers on various industrial applications, such as automated factory equipment, elevators, compactors, semiconductor fabrication devices, trucks, and more.

We do not restrict our customers from purchasing what is in stock; instead, we offer them custom-built switches tailored to their needs! We also price our products and services accordingly, ensuring that you receive the best solution at the most competitive rate.

Contact us today to learn more about our solutions and products!