MJ2955 Reference Tables | The Engineering Projects

Pin reference

Signal names, electrical functions and connection guidance

TO-204AA (TO-3)

Physical pin numbers3 pins

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MJ2955 pin functions and connections
Signal	Type	Function & connection
B	Base	Current-driven control junction. Connection guidance Use the example’s 330 Ω series drive and 10 kΩ base-emitter return. Bottom view of CASE 1-07: base 1 below emitter 2, offset toward the left mounting hole.
E	Emitter	Reference terminal for base drive. Connection guidance Connect to +12 V. Bottom view of CASE 1-07: base 1 below emitter 2, offset toward the left mounting hole.
C	Collector	The metal case is the collector; there is no third wire lead. Connection guidance Connect to the 100 Ω load above ground. Both mounting contacts belong to collector. Insulate the heatsink when required.

Selected manufacturer reference

Manufacturer-referenced values4 parameters

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Parameter	Value	Conditions / notes
Device	MJ2955	onsemi complementary power transistor family
Polarity	PNP	Voltages and currents below use magnitudes
Physical connection	B1 · E2 · case C3	Two insulated TO-3 leads; case is collector
Package	TO-204AA (TO-3)	CASE 1-07, style 1

No unverified SMD substitute is selected.

Do not combine maxima into one operating point

Manufacturer-referenced values7 parameters

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Parameter	Value	Conditions / notes
Collector-emitter VCEO	60 V	Open base
Collector-emitter VCER	70 V	100 Ω base-emitter resistor
Collector-base voltage	100 V	Absolute maximum
Emitter-base reverse voltage	7 V	Absolute maximum
Collector / base current	15 A / 7 A	Absolute maximum
Dissipation	115 W at case 25°C	Derate 0.657 W/°C
Junction / storage	−65 to +200°C	Absolute limits

Apply the manufacturer safe operating area.

25°C and stated manufacturer conditions

Manufacturer-referenced values5 parameters

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Parameter	Value	Conditions / notes
DC gain at 4 A	20–70	VCE magnitude 4 V
DC gain at 10 A	5 minimum	VCE magnitude 4 V
Saturation at 4 A / 400 mA base	1.1 V maximum	Case 25°C
Saturation at 10 A / 3.3 A base	3 V maximum	Case 25°C
Base-emitter on voltage	1.5 V maximum	IC magnitude 4 A; VCE magnitude 4 V

PNP test currents and voltages are negative in the source; magnitudes are shown.

Case and ambient conditions differ

Manufacturer-referenced values4 parameters

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The authored footprint is a starting pattern, not a manufacturer land recommendation.

Explicit low-current teaching assumptions

Manufacturer-referenced values6 parameters

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Parameter	Value	Conditions / notes
Supply and load	12 V / 100 Ω ≥3 W	Resistive load
Buffered driver	12 V off / 7 V on	330 Ω base resistor
Base-emitter return	10 kΩ	Defined off state
Assumed junction drops	\|VBE\| 0.8 V / \|VCE\| 0.2 V	Illustrative only
Collector / base current	118 mA / 12.65 mA	Includes base-return current
Device / load power	33.7 mW / 1.392 W	Includes base-emitter input power

Do not infer high-current capability from this small example.