The Guide to BD243 NPN Power Transistor [FAQ]

The BD243 and other NPN power transistors in this series, such as the BD243A, BD243B, and BD243C, are available in a TO-220 package. These transistors are intended for switching and amplification applications in general. The collector current of all of these transistors is 6A, however, the maximum collector to emitter voltage varies from 45V for the BD243 to 60V for the BD243A.  80V for the BD243B  and 100V for the BD243C.

However, if you're utilizing it in a design where you're driving a load under 45V, you can use any of the BD243/A/B/C transistors. However, if your load requires more than 45V, you can use the BD243B.  which can drive up to 80V, and if your load requires more than 80V, you can use the BD243C.

The maximum emitter to base voltage is 5 volts, the maximum power dissipation is 65 watts, and the minimum  DC  current gain is 15 to 30 percent.

Transistors are semiconductor electronic devices with three terminals that can be employed as switches or amplifiers. They can be NPN or PNP polarized, and there are several distinct varieties with various power and switching speed ratings. A power transistor is one that can tolerate more than 1 A of collector current when designed according to these principles.

BD243 Pinout

BD243 Symbol

BD243 Footprint

• Material of Transistor: Si

• Polarity: NPN 

• Maximum Collector  Power Dissipation (Pc): 65 W

• Maximum Collector  -Base Voltage |Vcb|: 55 V

• Maximum Collector-Emitter Voltage |Vce|: 45 V

• Maximum Emitter-Base Voltage |Veb|: 5 V

• Maximum Collector  Current |Ic max|: 6 A

• Max. Operating  Junction Temperature  (Tj): 150 °C

• Transition Frequency (ft): 3 MHz

• Forward Current Transfer Ratio  (hFE), MIN: 30

• Noise Figure, dB: -

• Package: TO220

• High Current Gain Bandwidth Product 

• These Devices are Pb−Free and are RoHS Compliant*

• Low Noise, High Efficiency, Long Life

• BMS Applications

• Motor Drivers

• Battery Chargers

• Driving or Switching  Loads  under 6A

• High Power Audio Amplifier Circuits 

BD537, 2N5497, 2N6121, 2N6123, 2N6288, 2N6289, 2N6290, 2N6291, 2N6292, 2N6293, 2SC1107, 2SC1109, 2SD476, 2SD1412, BD291, BD293, BD295, RCA1C10, RCA1C14, 2SC1108, 2SC1110

The BD243 transistors are general-purpose transistors that may be used in a wide range of electronic circuits. When employed as a switch, the transistor can drive up to 6A of current, which is sufficient to operate a range of motors, electronic switches, relays, high-power transistors, and other devices. On the other hand, it can be utilized for audio amplification and is capable of producing high-power audio amplifiers.

Connect the positive lead of the multimeter to the transistor's Base (B) and the negative lead to the transistor's Emitter (E). If it's an NPN  transistor, the voltage drop should be between 0.45V and 0.9V on the meter. If it's a PNP  transistor, it should show "OL" on the screen (Over Limit).

BD243 Package Outline

onsemi (formerly ON Semiconductor until August 5, 2021) is an American semiconductor supplier company, formerly in the Fortune 500, but dropping into the Fortune 1000 (ranked 512) in 2020. Products include power and signal management, logic, discrete, and custom devices for automotive, communications, computing, consumer, industrial, LED lighting, medical, military/aerospace and power applications.