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MJE3055 Transistor Data
Key transistor data for the MJE3055 NPN power transistor including key electrical parameters, pinout, package type and many other key transistor datasheet details.
The MJE3055 is a rugged power transistor widely used for amplifier and power switching circuits. It is the TO220 version of the iconic 2N3055 device used in many power audio amplifiers.
Key details and performance parameters for the MJE3055 transistor.
| Transistor parameters & data |
|
|---|---|
| Parameters | Details |
| Transistor type | NPN silicon switching transistor |
| Package type | TO220 |
| VCBO max (V) | 60 |
| VCEO max (V) | 60 |
| VEBOmax (V) | |
| IC max (A) | 10 |
| TJ Max °C | 150 |
| PTOT W | 90 |
| fT min (MHz) | 2 |
| COB | |
| hfe | 20 - 70 |
| IC for hfe | 4 A |
| Similar / equivalents | |
Outline:
Pinout:
Explanation of transistor parameters
| Parameter | Explanation |
|---|---|
| VCBO Max | Maximum collector-base voltage with emitter open circuit . |
| VCEO Max | Maximum collector-emitter voltage with base open circuit. |
| VEBO Max | Maximum emitter-base voltage with collector open circuit. |
| VCEsat (included where applicable) | The voltage drop across the collector-emitter when the transistor is fully saturated (acting as a closed switch). |
| IC Max | Maximum collector current. |
| Parameter | Explanation |
|---|---|
| TJ | Maximum junction temperature. |
| PTOT Max | Maximum device dissipation normally in free air at 25°C unless other conditions indicated. |
| fT Min | Minimum cutoff frequency at which the current gain in a common emitter circuit falls to unity. |
| COB Max | Maximum collector capacitane, normally measured with emitter open circuit. |
| hFE | DC current gain for HFE at IC. [Note hfe is the small signal gain and although this may be slightly different, the transistor current gain will vary considerably from ne transistor to the next of the same type.] |
| PTOT Max | Maximum device dissipation normally in free air at 25°C unless other conditions indicated. |
These are the main transistor parameters that have been included in our list. There are others, but these help quantify the main elements of the performance of the transistor.
Please note, that the data given is the best estimate we can give within a tabulated summary of this nature. Parameters also vary between manufacturers. Electronics Notes cannot accept any responsibility for errors, inaccuracies, etc, although we do endevaour to ensure the data is as accurate as possible.
Notes and supplementary information
The MJE3055 is a version of the iconic 2N3055 silicon NPN power transistor which was for many years the standard power transistor for power supplies, audio amplifier output stages and for many other circuits.
This TO220 version of the transistor has slightly lower ratings but for many applications it will be more than adequate.
• Availability & sources
The device is available from a number of stockists and electronic component distributors.
• Mounting the MJE3055
Like other transistors in a TO220 case, it is necessary to isolate the metal backplate of the transistor from the heatsink. A mica washer, together with an insulating washer for the screw fixing hole will provide the necessary mounting.
It is also wise to use from some thermal (silicone) grease to ensure good thermal contact between the transistor and the washer and then the washer and the heatsink.
• Availability
The MJE3055 transistor is still manufactured these days and can be obtained through a some distributors, although it is basically an obsolete component.
The technology is old, and it is easy to manufacture, and accordingly it is easy for smaller manufacturers to pick the fabrication techniques up.
Written by Ian Poole .
Experienced electronics engineer and author.
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