However, both the NPN & PNP type bipolar transistors can be made to operate as “ON/OFF” type solid state switch by biasing the transistors Base terminal differently operating the transistor as a switch.

So on a multimeter, it indicates a mode where the meter can measure (probably crudely), the HFE of a transistor.When used as an AC signal amplifier, the transistors Base biasing voltage is applied in such a way that it always operates within its “active” region, that is the linear part of the output characteristics curves are used.

HFE is an abbreviation, and it stands for ' Hybrid parameter forward current gain, common emitter', and is a measure of the DC gain of a junction transistor. The datasheets will normally specify whether the hFE value is for DC or AC current gain. hFE (which is also referred to as β) is the factor by which the base current is amplified to produce the amplified current of the transistor. HFE of a transistor is the current gain or amplification factor of a transistor. The 2n2222 part is the older style part which might be the reason they are being offered at a low price. But if you are not planning on stressing the part (higher voltages, etc) both will work well, especially for simple switching and logic circuits. The 2n2222A is a slight bit better in terms of Vceo, Vcbo, Vebo. What is the difference between 2N2222 and 2N2222A? Secondly, gain and leakage characteristics, PN2222A is properly a repackaging of 2N2222A, a better version of 2N2222. Firstly, package, PN2222 is in a molded-epoxy TO-92 2N2222 is in a TO-18 metal can. But there are subtle differences between them. The maximum amount of current that could flow through the Collector pin is 800mA, hence we cannot connect loads that consume more than 800mA using this transistor.įor most purposes, they are interchangeable. It is used as an amplifier to amplify voltage, current & power.ĢN2222 has a gain value of 110 to 800, this value determines the amplification capacity of the transistor. These transistors are used in Motor drive circuits like VFD or variable frequency drives. It is typically used in automation & embedded projects. In which device 2N2222 transistor is used? The 2N2222 has a combined rise-time, fall-time, and storage-time of 310ns, thus the maximum switching frequency is about 3MHz so it's not appropriate for this application. It was originally made in the TO-18 metal can as shown in the picture. It is designed for low to medium current, low power, medium voltage, and can operate at moderately high speeds. The 2N2222 is a common NPN bipolar junction transistor (BJT) used for general purpose low-power amplifying or switching applications. It has three terminals named as: Emitter. It's a Bipolar junction transistor abbreviated as BJT. It is designed for high-speed switching applications at collector currents up to 500 MA and features useful current gain over a wide range of collector current, low leakage currents, and low saturation voltages.ĢN2222 is an NPN transistor, which means it has a single P doped layer embedded between two N doped layers. You can download the datasheet of 2N2222 from the link given below:ĢN2222 FAQ What are 2N2222 High-Speed Switches ?ĢN2222 is a silicon planar epitaxial NPN transistor in Jedec TO-18 metal cases.

* Pulsed : pulse duration = 300 µs, duty cycle = 1 %. (T amb = 25 ☌ unless otherwise specified) SymbolĬolllector-base Breakdown Voltage (I E = 0)Ĭollector-emitter Breakdown Voltage (IB = 0)Įmittter-base Breakdown Voltage (I C = 0) They are designed for high-speed switching applications at collector currents up to 500 mA, and feature useful current gain over a wide range of collector current, low leakage currents and low saturation voltages.ĢN2218/2N2219 approved to CECC 50002-100, 2N2221/2N2222 approved to CECC 50002-101 available on request. The 2N2218, 2N2219, 2N2221 and 2N2222 are silicon planar epitaxial NPN transistors in Jedec TO-39 (for 2N2218 and 2N2219) and in Jedec TO-18 (for 2N2221 and 2N2222) metal cases.

2n2222 transistor switch circuit