2N3906 Transistor Pinout, Application Notes, and Equivalents

The 2N3906 is a common PNP (Positive-negative-Positive) bipolar junction transistor that was first made by Motorola in the mid-1960s for general purpose low-power amplifying and switching applications. It's made for low electric current and power, as well as medium voltage and a high working speed. It comes in a TO-92 small plastic case

2N3906 Transistor Pinout, Application Notes, and Equivalents
2N3906 Transistor Pinout

2N3906 Brief Description

The 2N3906 is a common PNP (Positive-negative-Positive) bipolar junction transistor that was first made by Motorola in the mid-1960s for general purpose low-power amplifying and switching applications. It's made for low electric current and power, as well as medium voltage and a high working speed. It comes in a TO-92 small plastic case. It features a 200 mA current rating, a 40 V voltage rating, and a 625 mW power rating. When a current of 10 mA flows through the collector, it yields a current gain of 100. Because of its strong gain and low saturation voltage, the 2N3N06 is widely used.

2N3906 Features and Technical Specifications

• Complementary of 2N3904/MMBT3904 bipolar transistor 

• Collector-Emitter Voltage (VCE): 40V

• Emitter Base Voltage (VBE): 5V

• Continuous Collector current (IC): 200mA

• Base Current(IB): 5mA maximum

• DC Current Gain (hFE): 300 maximum

• Available in To-92 Package

• Collector Base Voltage (VCB): 40V

• Pb-free packages option available

2N3906 Pinout

2N3906 pinout

Where to Use 2N3906 

The 2N3906 is a popular NPN transistor commonly used in these applications: 

• High to low current loads switching

• Inverter and converter circuits

• Darlington pair circuits

• Siren or dual-LED

• Low power amplification circuit

• Lamp flasher

2N3906 Delay and Rise Time Test Circuits

2N3906 test circuit

2N3906 Delay and Rise Time Test Circuits

2N3906 test circuit diagram

How to Use 2N3906

how to use 2N3906 transistor

By turning on the LED linked between the collector and ground, this circuit detects low light. Emitter current goes from emitter through the collector to Ground during low light conditions, lighting up the LED as it travels.

The 2N3906 is used as a switch in the circuit design above to turn on/off an LED connected at the collector terminal (depending on the surrounding light). A 9 V supply is used to power the entire circuit.

To protect the LED from overcurrent, a 5.6 K Ohm resistor is put between the load (LED) and Ground. Using Ohm's law, the requisite resistor value can be simply computed.

The base of the transistor is not biased when the light shining on the LDR is significant (low resistance). And zero -ve current flows to the transistor's base. As a result, the 2N3906 remains cut-off and the LED does not light up.

When the amount of light falling on the LDR is significant (low resistance), the transistor's base is not biased. And no current passes to the transistor's base. As a result, the 2N3906 remains in the cut-off state, and the LED does not light up.

When there is little light falling on the LDR (high resistance), the transistor's base is biased, and -ve current flows to the transistor's base. Because of the biasing current, the 2N3906 enters the saturation condition and the LED turns on.

2N3906 vs BC557

The BBC557 transistor is extremely close to the 2N3906. The 2N3906 is distinguished by its high collector to emitter voltage (VCE). Furthermore, because the part's gain value is only 300, it is incompatible with high-power amplifier application circuits.

(Summarized by Easybom)

2N3906 Equivalents/Alternatives

* Given below is the list of popular transistors which can be used as a replacement for 2N3906

2N3055 2N2222 BC108 BC527 KT315 BC548 BC559 C945 2N4403

2N3906 Datasheet

The 2n3906 transistor's electrical characteristics, current-voltage values, and physical dimensions are all detailed in this datasheet.

https://pdf.easybom.com/r/datasheets/onsemiconductor-2n3906ta-datasheets-1387.pdf