2N3904 Transistors

2N3904 Transistors Overview

Motorola Semiconductor registered in the mid-1960s, together with the complementary PNP type 2N3906, and represented a significant performance/cost improvement, with the plastic TO-92 case replacing metal cans. This transistor is low-cost, widely available and sufficiently robust to be of use by experimenters and electronics hobbyists.  When looking at the flat side with the leads pointed downward, the three wires emerging from the bottom are connected to, from left to right, the emitter, the base and the collector. Some manufacturers mark “EBC” on the moulded part, but all are required to have those connections for a part which is a “2N3904”.

It is a 200 mA, 40 V, 625 mW transistor with a transition frequency of 300 MHz, with a minimal beta, or current gain, of 100 at a collector current of 10 mA.

A bipolar junction transistor (BJT) is a transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipolar transistor allows a small current injected at one of its terminals to control a much larger current flowing between two other terminals, making the device capable of amplification or switching.

BJTs use two junctions between two semiconductor types, n-type and p-type, regions in a single crystal of material. Junctions can be made in several different ways, such as changing the semiconductor material’s doping as it is grown, by depositing metal pellets to form alloy junctions or by such methods as diffusion of n-type and p-type doping substances into the crystal. The superior predictability and performance of junction transistors soon displaced the original point-contact transistor. Diffused transistors, along with other components, are elements of integrated circuits for analogue and digital functions. Hundreds of bipolar junction transistors can be made in one circuit at a meagre cost.

Bipolar transistor

Bipolar transistor integrated circuits were the main active devices of a generation of mainframe and minicomputers. But most computer systems now use integrated circuits relying on field-effect transistors. Bipolar transistors are still used for amplification of signals, switching, and in digital circuits. Specialized types are used for high voltage switches. For radio-frequency amplifiers or switching heavy currents.

The 2N3904 is a through-hole, NPN silicon planar switching transistors in the TO-92 metal can package. This transistor features fast switching, short turn off and low saturation voltage. It is suitable for switching and amplification can operate at moderately high speeds.

Features:

• Package To-92(To-92-3)
• Brand Category Semtech
• Transistor Type Npn
• Collector emitter voltage (Vce) of 40V
• Continuous collector current (Ic) of 200mA
• Voltage – Collector-Emitter Breakdown Max 40 V
• Power – Max 625 mW
• 200°C/W Thermal Resistance,
• Operating junction temperature range from -55°C to 150°C

Reference

Playing with Transistors: NPN 2N3904 Transistor Experiment

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