Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi BD241CTU

Name: BD241CTU
Brand: onsemi
SKU: BD241CTU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: BD241CTU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: BD241CTU.pdf

Description:: TRANS NPN 100V 3A TO-220-3

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:2,914

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

BD241CTU from ON Semiconductor (formerly Fairchild) is an NPN epitaxial silicon power transistor in TO-220 package, rated for 100 V V_CEO, 3 A continuous collector current, and 40 W power dissipation at T_C = 25°C, used in medium-power linear regulation and switching applications such as DC motor control and power supply output stages.

For engineers reviewing the BD241CTU datasheet, pinout, applications, or equivalent options, key selection factors include its 100 V V_CEO, 3 A I_C, 1.2 V V_CE(sat) at 3 A/0.6 A drive, h_FE ≥ 10 at 3 A, and TO-220 thermal performance for industrial switching designs.

Technical Context

The BD241CTU operates as a medium-power NPN bipolar junction transistor optimized for linear and switching use with fixed-base drive capability. It features a V_CEO of 100 V and V_CER of 115 V, enabling robust operation under inductive load transients in relay drivers and power converters.

Its DC current gain h_FE is specified at 10 (min) at I_C = 3 A and V_CE = 4 V, and saturation voltage is tightly controlled at 1.2 V (max) under I_C = 3 A / I_B = 0.6 A, supporting efficient low-loss switching in 24–48 V systems.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	100 V - Maximum collector-emitter voltage before breakdown; enables use in 48 V bus switching and flyback snubbers.
I_C (DC)	3 A - Continuous collector current rating; supports medium-power loads like solenoids and fan motors.
P_C (T_C=25°C)	40 W - Thermal power limit at case temperature 25°C; requires heatsink for sustained >1 A operation.
V_CE(sat)	1.2 V max at I_C=3 A, I_B=0.6 A - Low saturation voltage reduces conduction loss in switching mode.
h_FE	≥10 at I_C=3 A, V_CE=4 V - Sufficient current gain for direct microcontroller GPIO drive without amplification.
T_J max	150 °C - Maximum junction temperature; defines thermal derating envelope for reliability in enclosed enclosures.

Pinout & Package

BD241CTU uses the standard TO-220 package with 3 leads: lead 1 = Base, lead 2 = Collector (tab-connected), lead 3 = Emitter. The metal tab is electrically connected to the collector and must be isolated from chassis ground unless circuit design intentionally references collector potential.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input terminal	Receives base current to bias transistor into active or saturation region; requires ~0.6 A for full 3 A switching.
2 (Collector)	High-side current path	Connected to metal tab; carries load current and dissipates heat; must be electrically isolated if mounted to grounded heatsink.
3 (Emitter)	Current return path	Serves as common reference node for base drive and load return; typically tied to system ground or low-side switch node.

Key Features

Feature	Design Value
100 V V_CEO rating	Supports operation across 48 V industrial buses and automotive 36 V nominal systems with margin for inductive kick.
TO-220 mechanical form	Enables standardized heatsinking and PCB mounting with industry-common footprint and screw-hole compatibility.
Complementary pairing	Designed as NPN counterpart to BD242CTU PNP, enabling push-pull and H-bridge configurations without redesign.
150 °C maximum junction temperature	Allows reliable operation in sealed enclosures up to ambient 85 °C when properly heatsinked per thermal resistance specs.

Applications

DC Motor Control	Linear Power Regulator
Use Scenario: Driving 24 V brushed DC motors in industrial actuators requiring bidirectional control via H-bridge. IC Role / Device Role / Timing Role: NPN switching element in high-side or low-side position; handles 2–3 A peak load current with fast turn-on/off. Use Value: 1.2 V V_CE(sat) minimizes I²R loss during conduction, improving efficiency and reducing heatsink size.	Use Scenario: Pass transistor in adjustable linear regulator supplying 5–12 V at up to 2.5 A for analog sensor subsystems. IC Role / Device Role / Timing Role: Series pass element operating in active region; dissipates excess voltage as heat under load. Use Value: 40 W power rating and 150 °C T_J enable stable regulation under worst-case dropout and load conditions.
Relay Driver Circuit	Switching Power Supply Output Stage
Use Scenario: Solid-state replacement for electromechanical relays controlling HVAC dampers or lighting ballasts. IC Role / Device Role / Timing Role: High-current switch interfacing microcontroller GPIO to inductive relay coil (75–150 Ω, 20–50 mA). Use Value: 100 V V_CEO safely clamps back-EMF spikes up to 115 V (V_CER), eliminating need for external snubber diodes.	Use Scenario: Main switching transistor in 100 W offline flyback or forward converter for industrial AC/DC supplies. IC Role / Device Role / Timing Role: Primary-side switch cycling at ≤100 kHz; conducts during on-time, blocks during off-time. Use Value: 100 V rating accommodates reflected output voltage plus leakage spike margin in 24 V output designs.

DC Motor Control

Linear Power Regulator

Use Scenario: Driving 24 V brushed DC motors in industrial actuators requiring bidirectional control via H-bridge.

IC Role / Device Role / Timing Role: NPN switching element in high-side or low-side position; handles 2–3 A peak load current with fast turn-on/off.

Use Value: 1.2 V V_CE(sat) minimizes I²R loss during conduction, improving efficiency and reducing heatsink size.

Use Scenario: Pass transistor in adjustable linear regulator supplying 5–12 V at up to 2.5 A for analog sensor subsystems.

IC Role / Device Role / Timing Role: Series pass element operating in active region; dissipates excess voltage as heat under load.

Use Value: 40 W power rating and 150 °C T_J enable stable regulation under worst-case dropout and load conditions.

Relay Driver Circuit

Switching Power Supply Output Stage

Use Scenario: Solid-state replacement for electromechanical relays controlling HVAC dampers or lighting ballasts.

IC Role / Device Role / Timing Role: High-current switch interfacing microcontroller GPIO to inductive relay coil (75–150 Ω, 20–50 mA).

Use Value: 100 V V_CEO safely clamps back-EMF spikes up to 115 V (V_CER), eliminating need for external snubber diodes.

Use Scenario: Main switching transistor in 100 W offline flyback or forward converter for industrial AC/DC supplies.

IC Role / Device Role / Timing Role: Primary-side switch cycling at ≤100 kHz; conducts during on-time, blocks during off-time.

Use Value: 100 V rating accommodates reflected output voltage plus leakage spike margin in 24 V output designs.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD243G	Same V_CEO (100 V), higher h_FE (20–100), TO-263 surface-mount package	Requires PCB rework for SMT layout; better suited for automated assembly and compact designs	Select when board space is constrained and thermal interface allows SMT heatsinking.
BD241C	Identical electrical specs and TO-220 package; BD241CTU is the tape-and-reel variant of BD241C	No functional difference; BD241CTU is optimized for automated pick-and-place assembly	Choose BD241CTU for volume production with SMT placement equipment; BD241C for manual or low-volume through-hole use.

Compared with MJD243G and BD241C, the BD241CTU offers identical core switching performance in a through-hole TO-220 format with tape-and-reel packaging-making it optimal for mixed-technology boards where legacy through-hole assembly coexists with automated processes.

Availability

BD241CTU is available at Aetrix Electronics and suitable for DC motor control, linear power regulation, relay driving, and switching power supply output stages requiring stable component supply and long-term industrial availability.

Supply support for BD241CTU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, and IoT applications.

The BD241CTU belongs to ON Semiconductor's legacy power bipolar transistor family, designed specifically for cost-sensitive, medium-power linear and switching applications where ruggedness, thermal stability, and proven reliability are critical.

FAQ

What is the maximum collector-emitter voltage rating for BD241CTU?

The BD241CTU has a maximum collector-emitter voltage (V_CEO) rating of 100 V at T_C = 25°C. This rating ensures safe operation in 48 V industrial systems with transient margin. Its V_CER (collector-emitter voltage with base open) is 115 V, providing additional headroom for inductive load switching. Always verify derating curves in the official BD241CTU datasheet for elevated temperature operation.

Is BD241CTU pin-compatible with BD241C?

Yes, BD241CTU is pin-compatible with BD241C - both share identical TO-220 package dimensions, pinout (Base–Collector–Emitter), and electrical specifications. The "TU" suffix denotes tape-and-reel packaging for automated assembly, while BD241C is typically supplied in tube format. No PCB layout changes are required when substituting BD241CTU for BD241C in production.

What is the typical DC current gain (h_FE) of BD241CTU at 3 A collector current?

The BD241CTU specifies a minimum h_FE of 10 at I_C = 3 A and V_CE = 4 V. Typical values range between 15 and 30 depending on unit variation and temperature. This gain level supports direct drive from logic-level outputs (e.g., 5 V MCU GPIO with series resistor), though base current limiting must ensure I_B ≥ 0.3 A for guaranteed saturation.

Does BD241CTU require a heatsink in normal operation?

Yes, BD241CTU requires a heatsink when conducting more than ~1 A continuously or operating at ambient temperatures above 50°C. With a junction-to-case thermal resistance (R_θJC) of approximately 0.625 °C/W and 40 W maximum power dissipation, even modest power levels (e.g., 5 W) raise the junction temperature significantly without thermal management. Mounting to a 20 °C/W heatsink keeps T_J within 150 °C at 3 A DC load.

What is the complementary PNP transistor for BD241CTU?

The complementary PNP transistor for BD241CTU is BD242CTU - same voltage ratings (100 V V_CEO), current capability (3 A), TO-220 package, and tape-and-reel packaging. Together, BD241CTU and BD242CTU form a matched pair for push-pull amplifiers, H-bridge motor drivers, and complementary linear regulators, ensuring symmetrical performance and thermal tracking.

BD241CTU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 3 A

Voltage - Collector Emitter Breakdown (Max):: 100 V

Vce Saturation (Max) @ Ib, Ic:: 1.2V @ 600mA, 3A

Current - Collector Cutoff (Max):: 300µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 25 @ 1A, 4V

Power - Max:: 40 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

BD241CTU FAQ

1.How can I place an order for BD241CTU through Aetrix?

Please submit a Request for Quotation (RFQ) for BD241CTU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BD241CTU reliable?

The price and inventory of BD241CTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BD241CTU is usually 5 days.

3.What payment methods are accepted for BD241CTU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BD241CTU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BD241CTU?

BD241CTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BD241CTU order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BD241CTU?

For technical support, including BD241CTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BD241CTU requirements.

6.How does Aetrix verify that BD241CTU is sourced from the original manufacturer or authorized distributors?

All BD241CTU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BD241CTU meets industry standards.

7.What is the process for return or replacement of BD241CTU?

All BD241CTU units undergo pre-shipment inspection (PSI). If there is an issue with BD241CTU, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BD241CTU part is unused and in its original packaging.

Return procedure for BD241CTU:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…