2N3055 Transistor Guide: RCA, Solitron & ASI NOS, Datasheet Specs, Pinout, Heat Sink Mounting & TO-3 Equivalents
Share
The 2N3055 transistor — a 60 V, 15 A, 115 W NPN power transistor in a TO-3 (TO-204AA) metal case — is in stock as new old stock (NOS) from RCA, Solitron, and ASI at American Industrial Parts Group, and new listings are added daily. This guide covers the 2N3055 datasheet specifications, pinout, and mounting, plus higher-voltage and Darlington TO-3 alternatives. It is part of our obsolete electronic components series; see the obsolete electronic components overview and our guide to vintage logic ICs and memory chips, then browse Vintage Power Transistors.
TO-3 Power Transistors We Stock
| Part | Type | Key specification | Complement | Collection |
|---|---|---|---|---|
| 2N3055 (RCA, Solitron, ASI) | NPN silicon power | 60 V VCEO, 15 A, 115 W, TO-204AA (TO-3) | MJ2955 (PNP) | Vintage Power Transistors |
| 2N3773 | NPN silicon power | 140 V VCEO, 16 A, 150 W, TO-204AA | 2N6609 (PNP) | Vintage Power Transistors |
| 2N6250 | NPN silicon power | 275 V VCEO, 10 A, TO-204AA (power rating varies by manufacturer; see listing) | See listing | Vintage Power Transistors |
| MJ4030 | PNP Darlington | 60 V, 16 A, 150 W, TO-3 | MJ4035 (NPN) | Vintage Power Transistors |
| MJ11033 | PNP Darlington | 120 V VCEO, 50 A, 300 W, TO-204 (TO-3) | MJ11032 (NPN) | Vintage Power Transistors |
| 2N6543, 2N4398 | NPN and PNP power, TO-3 | See product listings | See listings | Vintage Power Transistors |
| ECG283 / NTE283 | NPN high-voltage power, TO-3 | See product listing | See listing | NTE & ECG Cross-Reference |
2N3055 Datasheet Specifications and Pinout
These values come from the ON Semiconductor 2N3055 datasheet. Always compare against the datasheet for the specific manufacturer's part.
- Collector-emitter voltage (VCEO): 60 V
- Collector-base voltage (VCB): 100 V
- Emitter-base voltage (VEB): 7 V
- Continuous collector current (IC): 15 A
- Base current (IB): 7 A
- Power dissipation (PD): 115 W at 25°C case temperature
- DC current gain (hFE): 20 to 70 at 4 A
- Collector-emitter saturation voltage: 1.1 V maximum at 4 A
- Thermal resistance, junction to case: 1.52 °C/W
- Junction temperature range: -65°C to +200°C
2N3055 pinout (TO-204AA / TO-3): pin 1 is the base, pin 2 is the emitter, and the metal case is the collector.
2N3055 Mounting and Heat Sink Notes
- The case is the collector: the metal case is electrically connected to the collector, so check your mounting and insulation hardware.
- Power rating depends on case temperature: the 115 W rating applies at a 25°C case temperature and derates by 0.657 W per °C above that, so the case must be kept cool to use the transistor near its rated power.
- Thermal resistance: the datasheet lists 1.52 °C/W from junction to case. The heat sink is what removes heat from the case.
- Hardware: sockets, insulators, and heat sinks are not included unless listed.
How to Read TO-3 Power Transistor Part Numbers
- TO-3 and TO-204AA: TO-204AA is the JEDEC designation for the TO-3 style metal case. Datasheets use both names for the same package.
- Same number, multiple manufacturers: the 2N3055 has been made by many companies, and we stock RCA, Solitron, and ASI versions. The MJ11033 appears in datasheets from onsemi and Semelab.
- Date codes: many manufacturers stamp a year and work-week code on the part. The onsemi 2N3055 marking, for example, includes the year and work week.
- NPN, PNP, and Darlington: a Darlington packs two transistors in one case for high current gain. The MJ11033, for example, specifies a minimum gain of 1,000 at 25 A.
- Complementary pairs: NPN and PNP parts designed to work together, such as 2N3055 / MJ2955, 2N3773 / 2N6609, and MJ11032 / MJ11033.
- NOS (new old stock): unused parts manufactured years ago and never installed.
Common Power Transistor Problems and What to Do
- Output transistors keep failing in an amplifier or power supply: find out why they failed before installing new ones, and replace them as a matched set.
- Need a 2N3055 replacement: the closest match is a 2N3055 from another manufacturer. Compare the datasheet ratings: 60 V VCEO, 15 A, 115 W.
- Need more voltage than a 2N3055: the 2N3773 is rated 140 V and 16 A, and the 2N6250 is rated 275 V and 10 A.
- Need a PNP complement: the MJ2955 pairs with the 2N3055 and the 2N6609 pairs with the 2N3773.
- Original part is discontinued: STMicroelectronics lists the MJ4035, the NPN complement of the MJ4030, as obsolete. NOS stock lets you buy the original part.
- Need matched parts for a full repair: many items are available in lots of 10.
Compatibility Notes Before You Order
- Check the package: some of our power transistors, such as the 2N3738 and ECG286, are TO-66, which is a different package from TO-3.
- Darlington vs. single transistor: a Darlington is not a drop-in for a single transistor of the same polarity.
- Ratings by manufacturer: compare the datasheet for the specific manufacturer's part, not just the part number.
- Condition: each listing states whether the part is NOS, new, or used.
2N3055 Transistor FAQ
What is the 2N3055 pinout?
On the TO-204AA (TO-3) package, pin 1 is the base, pin 2 is the emitter, and the metal case is the collector.
What is a 2N3055 equivalent?
The closest equivalent is a 2N3055 from another manufacturer. The ON Semiconductor 2N3055 is rated 60 V VCEO, 15 A, and 115 W. We stock RCA, Solitron, and ASI versions, and the PNP complement is the MJ2955.
Does a 2N3055 need a heat sink?
The 115 W rating applies at a 25°C case temperature and derates by 0.657 W per °C above that, so the case must be kept cool to use the transistor near its rated power.
How often is new inventory added?
New vintage power transistors are added to the site daily. Check the collections below for the latest listings.
Shop Vintage Power Transistors
Browse our growing inventory, tested, graded, and ready to ship: