Other switching transistors Pinout of 2N2222 variants in plastic TO-92 package.
It is used in a variety of analog amplification and switching applications. Therefore, it is important to refer to the datasheet for the exact part number and manufacturer.Īll variations have a beta or current gain (h fe) of at least 100 in optimal conditions. The exact specifications depend on the manufacturer, case type, and variation. Other part numbers will have different parameters. JEDEC registered parameters include outline dimensions, small-signal current gain, transition frequency, maximum values for voltage withstand, current rating, power dissipation and temperature rating, and others, measured under standard test conditions.
PN2222 REGISTRATION
The JEDEC registration of a device number ensures particular rated values will be met by all parts offered under that number. Since then it has been made by many semiconductor companies, for example, Texas Instruments. The 2N2222 was part of a family of devices described by Motorola at a 1962 IRE convention. It is frequently used as a small-signal transistor, and it remains a small general purpose transistor of enduring popularity. The 2N2222 is considered a very common transistor, and is used as an exemplar of an NPN transistor. It was originally made in the TO-18 metal can as shown in the picture.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. Cross section of 2N2222 in metal TO-18 package, showing connection wires between external pins and die. I'm guessing there's some kind of aspect of MOSFET I'm not understanding.2N2222A in metal TO-18 package with the emitter, base and collector identified as E, B, and C respectively. As it stands, the MOSFET gets VERY hot, and isn't doing half the job a darlington pair did without getting even a little warm. Thoughts? Am I missing something? (likely). If I short the source and drain, the array is fully on, but through the mosfet, it's greatly reduced.
I've even added a resistor to drop the 12v going to the collector, bringing the emitter voltage to around 8v. I can't seem to get the MOSFET to turn on fully given this setup, what gives? When I meter it, the pn2222 is feeding the gate over ten volts.
PN2222 PLUS
When I meter it, the pn2222 puts out a solid ten volts plus from the emitter. I've got a 470k resistor between the gate and ground also to bleed off the charge. The MOSFET drain is taking the ground side of an LED array drawing three amps at 12v (current regulated), and the source to ground. So, I have a bunch of pn2222, I just put a 1k from base to arduino, collector to 12v (common ground), and the emitter to the gate of the MOSFET.
PN2222 FULL
After reading all over the net and even here, I now understand that's minimum threshold, not full on. By reading it, I thought (as I was to learn) that VGS of 5v would be plenty. but I happened to be near Radio shack today, so I went in and got the only MOSFET they carry. So I have some logic level MOSFET's on order, they should be here middle of the week next week.
0 kommentar(er)
