2N3904
Encyclopedia
The 2N3904 is a common NPN bipolar junction transistor
used for general purpose low-power amplifying
or switching applications. The type was registered by Motorola Semiconductor in the mid-sixties, together with the complementary PNP type 2N3906, and represented a significant performance/cost improvement, with the plastic TO-92 case replacing metal cans. It is designed for low current
and power
, medium voltage
, and can operate at moderately high speeds. This transistor is low cost, widely available and sufficiently robust to be of use by experimenters. When looking at the flat side with the base pointed downward, the three wires emerging from the base are, left to right, the emitter, base and collector leads.
It is a 200 milliamp, 40 volt
, 625 milliwatt transistor with a transition frequency of 300 MHz, with a beta or current gain of 100 on minimum. It is used in a variety of analog amplification and switching applications.
Electrically similar devices are available in a variety of small through-hole and surface mount packages including TO-92, SOT-23, and SOT-223, with package-dependent thermal ratings from 625 milliwatts to 1 watt
.
A 2N3906
is a complementary (PNP) transistor for the 2N3904. The 2N2222
is an NPN transistor that can safely switch three times as much current as the 2N3904 but has otherwise similar characteristics. Nevertheless, in many applications such as variable frequency oscillators where lower currents are used to minimize thermal heating and consequent thermal drift of the fundamental frequency, the greater current capacity of the 2N2222 gives it no advantage.
The 2N3904 is used very frequently in hobby electronics circuits including home-made ham radios, code practice oscillators and as an interfacing device for micro-controllers.
Bipolar junction transistor
|- align = "center"| || PNP|- align = "center"| || NPNA bipolar transistor is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons...
used for general purpose low-power amplifying
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...
or switching applications. The type was registered by Motorola Semiconductor in the mid-sixties, together with the complementary PNP type 2N3906, and represented a significant performance/cost improvement, with the plastic TO-92 case replacing metal cans. It is designed for low current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
and power
Electric power
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
, medium voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
, and can operate at moderately high speeds. This transistor is low cost, widely available and sufficiently robust to be of use by experimenters. When looking at the flat side with the base pointed downward, the three wires emerging from the base are, left to right, the emitter, base and collector leads.
It is a 200 milliamp, 40 volt
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
, 625 milliwatt transistor with a transition frequency of 300 MHz, with a beta or current gain of 100 on minimum. It is used in a variety of analog amplification and switching applications.
Electrically similar devices are available in a variety of small through-hole and surface mount packages including TO-92, SOT-23, and SOT-223, with package-dependent thermal ratings from 625 milliwatts to 1 watt
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
.
A 2N3906
2N3906
The 2N3906 is a common PNP bipolar junction transistor used for general purpose low-power amplifying or switching applications. Compared to the general run of silicon transistors, it is designed for low current and power and medium voltage, and can operate at moderately high speeds...
is a complementary (PNP) transistor for the 2N3904. The 2N2222
2N2222
The 2N2222 is a common NPN bipolar junction transistor used for general purpose low-power amplifying or switching applications. It is designed for low to medium current, low power, medium voltage, and can operate at moderately high speeds. It is made in the TO-18 metal can as shown in the picture...
is an NPN transistor that can safely switch three times as much current as the 2N3904 but has otherwise similar characteristics. Nevertheless, in many applications such as variable frequency oscillators where lower currents are used to minimize thermal heating and consequent thermal drift of the fundamental frequency, the greater current capacity of the 2N2222 gives it no advantage.
The 2N3904 is used very frequently in hobby electronics circuits including home-made ham radios, code practice oscillators and as an interfacing device for micro-controllers.