What is a power transistor?
The transistor is the basic block of electronics, it is a semiconductor device that handles the voltage and current variations to a proper circuit operation.
A transistor is used for switching and amplifier application at circuits, but the power transistor had the ability to handle higher power signals without damaging its whole body.
Difference between normal transistors and power transistors?
We already mentioned transistors, it is a silicon semiconductor-based device that is used to handle current and voltage quantities, but transistors are the current controlling device.
Transistors are used for switching and amplification applications, these signal variations are been applied to different circuits.
Power transistors are devices that can handle higher power values, the power transistor is mainly capable of handling higher current values.
A power transistor is just like a normal transistor but it is capable of withstanding higher power values than normal transistors, which means the power transistor component body itself is harder to withstand, and also we can easily attach heat sinks with it.
Types of power transistor
- Bipolar Junction Transistor (BJT)
- Metal Oxide Semiconductor Field Effect Transistor (MOSFET)
- Insulated Gate Bipolar Transistor (IGBT)
- Static Induction Transistor (SIT)
- Field Effect Transistor (FET)
Symbol of the power transistor
The figure shows the symbol of BJT transistors such as NPN and PNP, the power transistors had the same symbol as the normal transistor.
But each power transistor type we listed above have different symbolic representations, this is because they all have different structural details and have different type of operation.
Working of the power transistor
The working of the Power transistor is the same as our normal transistor, the transistor is a three-terminal and three-layer semiconductor device that works as amplifiers and switches.
When we consider the working operation of a power transistor, the current carry capacity of the power transistor is higher than the normal transistor.
The three terminals of the transistor such as emitter, collector, and base are the connections taken out from the three layers of the transistor.
At the transistor component itself, we can categorize its terminals as input and output, the input of the transistor is between base-emitter, and output of the transistor is between base-collector, then the base terminal is the trigger of the transistor.
We already mention that transistors are commonly used for amplifiers and switching applications.
Graphical representation of power transistor
The figure shows the characteristics curve of the Power transistor, which shows three different operation regions of the power transistor.
Mainly breakdown region, cutoff region, active region, and saturation region are the regions.
Power transistor as a switch
When the power transistor works as a switch, the working is done between saturation and cutoff region, the ON and OFF switching operation is done between these operation regions.
Power transistor as an amplifier
When a transistor works as an amplifier, the transistor will work on active or linear
In the region, at active or saturation, the maximum capability of the transistor will be utilized.
Applications of power transistor
- Switched-mode power supply (SMPS)
- Relays
- Converters
- Power amplifier
- DC to AC converters
- Power supply systems
- Power control circuits
- Inverters
- Voltage regulator circuits
- Used for integrated circuits
- Used at touch switch applications
- Used at communications such as radar, etc.
Explain the main applications of the Power transistor
-
Switched-mode power supply (SMPS)
The main application based on power transistor is the switching, the switched-mode power supply (SMPS) are been works with a combination of multiple switching sections.
-
Power amplifier
The power transistors had an important role play in power amplifier circuits, normally amplifiers dissipate a higher amount of heat, this is because they can handle a higher amount of power.
Power transistor list
| Transistor list | Type | Collector-Emitter | Collector Current | DC Current Gain | Power Dissipation |
|---|---|---|---|---|---|
| Voltage (VCE) | (IC) | (hFE) | (PD) | ||
| 2N3055 | NPN | 60V | 14A | 20 to 70 | 155W |
| 2N6036 | PNP, Darlington | -80V | -4A | 750 to 15000 | 40W |
| 2N6039 | NPN, Darlington | 80V | 4A | 750 to 15000 | 40W |
| 2N6109 | PNP | -50V | -7A | 30 to 150 | 40W |
| BD139 | NPN | 80V | 1.5A | 40 to 250 | 12.5W |
| BD140 | PNP | -80V | -1.5A | 40 to 250 | 12.5W |
| MJE2955 | PNP | -60V | -10A | 20 to 70 | 75W |
| MJE3055 | NPN | 60V | 10A | 20 to 70 | 75W |
| MJE13007 | NPN | 400V | 8A | 8 to 40 | 80W |
| TIP31C | NPN | 100V | 3A | 10 to 50 | 40W |
| TIP32C | PNP | -100V | -3A | 10 to 50 | 40W |
| TIP35C | NPN | 100V | 25A | 15 to 75 | 125W |
| TIP36C | PNP | -100V | -25A | 15 to 75 | 125W |
| TIP41C | NPN | 100V | 6A | 15 to 75 | 65W |
| TIP42C | PNP | -100V | -6A | 15 to 75 | 65W |
| TIP48 | NPN | 300V | 1A | 30 to 150 | 40W |
| TIP50 | PNP | -400V | -1A | 30 to 150 | 40W |
